The young man known on the streets as "Tez Blood" was leaning over his best friend's bullet-pierced body, sobbing, when his cellphone rang with a call from a fellow gang member in prison.

"Somebody gonna go to sleep tonight, bro," he allegedly told the caller in May 2016, using slang for a revenge killing. "Somebody gotta feel how I feel, bro." Minutes later, his phone went off again. It was another inmate, urging him to avenge the death of their friend, Derrick Rodgers.

Police believe he took the advice to heart.

In fact, they've linked the 25-year-old to a series of killings and shootings, including a slaying that may have precipitated Rodgers' death last spring, according to court filings based on intercepted jailhouse phone conversations and information from confidential informants. But he hasn't been charged with any of them.

Much of Minneapolis' alarming rise in shootings in recent years seems to be the handiwork of a relatively small number of gunmen, police say. Designated "shooters" carry out tit-for-tat killings on behalf of their gang, quick to pull a trigger over old scores and insults. While the number of people shot citywide has dropped since last year, the brazenness of some attacks has police on high alert. As recent cases have shown, stopping the violence is frustrating.

"Yes, we do know many of these members that are likely to be involved in gun violence, but there's a multitude of different reasons of why they might still be out on the streets," said Assistant Minneapolis Police Chief Mike Kjos, citing reluctant witnesses and little evidence. And even when police make arrests, Kjos said, it can take months for results from ballistics and DNA tests. In the meantime, suspects often end up released from custody, and the violence continues.

Department statistics show that last year police cleared 35 percent of serious assault cases, which include shootings and stabbings. Charges were brought in 30 percent of the cases in 2016, compared with 26 percent the previous year.

Some of the main offenders are under federal investigation on weapons violations, court records reveal. But such investigations can be time-consuming and complex, authorities say. Police often pursue federal charges in gun cases because they carry heftier sentences.

Interrupting the cycle of retaliation is a constant challenge. Police arrest those they think are responsible. But without evidence to support criminal charges, many are back on the streets within 48 hours. Although police efforts have led to the seizure of 692 guns in 2017, according to the most recent department data available — roughly 54 percent more than were recovered by this time last year — a seemingly bottomless pool of weapons and shooters sustains the violence.

Police are sometimes left to weigh not arresting someone threatening violence against the possibility that they will carry out those threats.

As a former homicide investigator, Deputy Police Chief Erick Fors said there were cases when "investigatively, it's not a very good time to go arrest somebody, but we're really obligated to go arrest somebody."

"That's a moral obligation that we have," he said. "We don't want to have violent people running around."

Chain of violence

The latest chain of gang shootings began with the drive-by killing of Roy "Dolo" Davis in May 2016 during a gathering of Low End-affiliated gang members to remember another slain gang leader on the North Side. Seven others were wounded. An informant told police that "Tez" and other Taliban/Young and Thuggin' gang members were behind the shooting. "Tez" is not being formally named by the Star Tribune because he hasn't been charged with any of the shootings.

A week later came the shooting of Rodgers, aka "Li'l D," who was gunned down as he fled from pursuing gang members on Olson Highway. Police suspect it was in retaliation for Davis' slaying. The drive-by shooting of Crystal Collins followed two months later, in which police say the gunmen's intended target used the 36-year-old mother of three as a human shield. Tez's name has popped up in court filings as a suspect in that homicide (although police later developed another suspect) and at least one other shooting, last fall near a North Side highway entrance ramp.

A family member said that because of his reputation, Tez's name often surfaced in street rumors in connection with shootings that he had nothing to do with. The relative declined to use her name out of fear of retaliation, saying that her mother's house had been shot at least once. She described him as an outgoing but misguided young man who had fallen in with the wrong crowd.

"It could be like a holiday and he could be at the dinner table and as soon as there's a shooting, we'll see on Facebook and they'll say [Tez] did it," she said.

After a shooting, or threatening Facebook post — gang-unit officers hit the streets, knocking on doors of gangsters who might pick up a gun in retaliation.

At times, police have intervened before any shots were fired.

When, in the fall of 2014, authorities learned that members of the 1-9 Dipset and the Stick Up Boys gangs were stashing weapons, including automatic assault rifles, in a rental locker in anticipation of a revenge attack, they moved quickly. Agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives arrested 11 people, all of whom were already under federal investigation. In addition to drug trafficking, the group was indicted on gun charges, with authorities claiming that their ongoing feud with rival gangs had resulted in at least six killings and numerous shootings in the previous five years. According to federal court documents, one of the gang members later told authorities that "it was a good thing you came when you did because we were just about to go shoot them up."

But it isn't just the lack of evidence that makes solving gun violence difficult. Disagreements can emerge between detectives and prosecutors over whether or not to charge a suspect.

Hennepin County Attorney Mike Freeman and Hennepin County Chief Public Defender Mary Moriarty have said in separate interviews with the Star Tribune that investigators know who killed 2-year-old Le'Vonte King Jason Jones in July 2016 when the van he was riding in was riddled with bullets, also wounding his sister, who was 15 months old. Homicide detectives later arrested a man in the shooting and turned the case over to prosecutors in the county attorney's office, who declined to press criminal charges.

With conflicting witness accounts and little physical evidence to work with, prosecutors said any case they brought against the man was likely to fall apart in court.

Freeman said the case reflected a "healthy tension" that sometimes exists between his office and police.

"We want to charge it as much as they do, but we spend a lot more time in courtrooms than they do, and we read a lot more court cases," said Freeman said. "And a lot of times, cops don't like it."

Tez's only felony conviction is for a 2013 armed robbery. He got a stayed sentence, but in January was caught with drugs at a north Minneapolis gas station, violating his probation.

A raid of his home also yielded guns and drugs where children were present, court documents show.

At a court hearing to revoke his probation, he pleaded for leniency:

"It started almost a year ago, life been dealing me a hard hand, a losing hand; May 11th, 2016, I lost my best friend to gun violence with him being mistaken for someone else," he said, according to a court transcript. "I'm still dealing with his death."

He was sentenced to prison in May with a scheduled release date in November 2019.

Libor Jany • 612-673-4064 Twitter:@StribJany