Abdirahman Mohamed pushed his way through the crowd that gathered at Karmel Mall on Tuesday afternoon, in search of answers.

What he got instead was only frustration — a day after his father was gunned down on a south Minneapolis street, police still didn't know who shot him or why.

"The killings are like a cancer in our community," said Mohamed, who drove 14 hours through the night from his home in Nashville after hearing the news that his father, Abdi Haji Mohamed Liiban, had been killed Monday afternoon. "They have to be stopped."

In a span of one week, eight people have been fatally shot in Minneapolis and St. Paul in a run of gun violence that has alarmed even veteran police officers.

Liiban's death was the fifth homicide in Minneapolis in the past week and the 40th in the city this year, putting it on pace to record the most homicides in about a decade.

Four of the five slayings in Minneapolis, and two of the three in St. Paul, remain unsolved. Police insist that the violent outbursts are not random, and they are exploring motives that range from gang ties to domestic violence.

In response to the spike, officers in both cities have fanned out in recent days to hot spots to talk with residents and merchants unnerved by the killings and reassure them they were working to catch those responsible.

In St. Paul, extra officers have been deployed to the East Side, where all three shootings in the past week took place. The most recent victim, Sarah Anne Wierstad, 24, was shot just steps away from her front door Sunday night as she walked home from work in the Railroad Island area.

In Minneapolis, police officers spread out across the Fifth Precinct on Tuesday and visited a bustling Somali market and local community centers, not far from where Liiban died.

"This city is a community that's hurting," Minneapolis Police Chief Janeé Harteau told reporters the night before at the scene of Liiban's killing. "This community needs peace; we need people to put the guns down."

Shootings not connected

Liiban, a Somali immigrant who had lived in Minneapolis for 15 years, was shot about 4:45 p.m. Monday as he walked to work at a nearby high-rise residential complex. Officers found him lying in the street, less than two blocks from the Horn Towers, where he worked nights as a security guard.

Witnesses described the suspect as a young male, clad in a black hooded sweatshirt and jeans, according to a traffic scanner recording posted on the MN Police Clips Facebook page. He was seen getting into a black car that sped north on Pleasant Avenue, witnesses told police.

Four homicide detectives spent the better part of the night scouring the crime scene for spent bullet casings and physical evidence.

Police said the shooting didn't appear to be connected to another fatal shooting last weekend, in which officers found a man with gunshot wounds in an alley in the 3700 block of 1st Avenue S. That man, whose name hasn't been released, was taken to an area hospital, where he died early Monday, police said.

Breaks in several of the Minneapolis cases have so far proven elusive, and police have complained that few witnesses have come forward. Some who know what happened are afraid to talk for fear of retaliation, police said.

"I urge anyone to come out, not to be afraid. This is our community," said Jibril Afyare, a community activist and president of the Somali Citizens League.

The apartment complex where Liiban worked was the first stop for officers offering reassurance Tuesday. Residents there remembered him as a quiet, friendly man who took pride in his job.

He wouldn't hesitate to put out troublemakers who managed to slip into the secure building's lobby, but was just as quick to offer a smile and a wave to residents, said Carol Reiland, who has called the Towers home for two decades.

"He was a man who was committed to his job, and he was a man who could separate those doing good from the wrongdoers," Maryan Mohamed, another resident, said through an interpreter.

Ahmed Noor nodded as others shared memories. Afterward, he recalled receiving a phone call from Liiban just last week to congratulate him on the birth of his first child.

"He was a good guy. He cared about the community," Noor said.

Across the river in St. Paul, officers were busy patrolling the city's East Side, where five people have been fatally shot in the past four weeks within a 1.5-square-mile area.

The city has recorded 10 homicides so far this year, compared with 11 total in 2014.

Flowers and heart-shaped balloons marked the spot outside Wierstad's house where she died two nights earlier. By late in the day, police still had not made an arrest or provided details about why she was shot.

Police are asking for the public's help in providing information about Wierstad's death and several other shootings, said police spokesman Steve Linders. A $1,000 reward also has been offered for information that would help solve the mystery of the Oct. 5 fatal shooting of Htoo Baw, a 54-year-old Karen immigrant, as he was unloading his car outside his house.

Late Monday afternoon, St. Paul police got a break in one of the cases when a 21-year-old man was arrested in the murder of Emmett L. Wilson-Shaw, who was shot on the Earl Street Bridge last week. The suspect, who has a robbery conviction on his record, has yet to be charged.

"It takes time," Linders said about arresting suspects. "It's just the matter of going through the investigation process."