The killings of four people whose bodies were found last week in a bloodied SUV in a western Wisconsin farm field occurred in St. Paul and not where the discovery was made, authorities said Monday.

The St. Paul Police Department is now the lead agency in the investigation of the deaths of Matthew Pettus, 26, and half-sister Jasmine C. Sturm, 30, both of St. Paul; Sturm's boyfriend, 35-year-old Loyace Foreman III, also of St. Paul; and 30-year-old Nitosha Flug-Presley of Stillwater, a close friend of Sturm's.

The four were found by a farmer inside an abandoned black Mercedes SUV in a cornfield on Sept. 12 just outside of the Town of Sheridan in Dunn County, roughly 60 miles east of St. Paul.

As more about the deaths surfaces, a significant question in connection with the city's largest mass killing in nearly a quarter-century remains a mystery: Why?

"We still [have] got an active investigation, and I'm not certain that an exact motive has been determined yet," said St. Paul police spokesman Steve Linders.

St. Paul police on Wednesday arrested 56-year-old Darren McWright of St. Paul, who also goes by the last name Osborne, in connection with the deaths. He's being held in the Ramsey County jail on several outstanding warrants, including at least one out of Dunn County.

On Friday, McWright's son, Antoine D. Suggs, 38, of Scotts-dale, Ariz., turned himself in to Gilbert, Ariz., police after investigators announced he was wanted for questioning. He remains jailed in Arizona, awaiting extradition.

"After gathering evidence and information about what happened before and after the bodies were discovered, investigators concluded the killings occurred in Minnesota," specifically St. Paul, the city's Police Department announced.

There have been no descriptions of who shot the victims or where the shootings took place other than in St. Paul, but authorities said in court documents that Suggs was seen at a St. Paul bar with Flug-Presley and two of her friends hours before they were found dead along with a fourth victim.

The Ramsey County Attorney's Office said cases have not yet been forwarded for possible charges. However, criminal complaints filed Wednesday against McWright and Suggs on "hiding a corpse" charges spell out some of the events leading up to the killings and how authorities caught up to the defendants:

Suggs was implicated in the deaths after crime lab personnel recovered his Arizona photo identification card from the bloodied black Mercedes SUV, which had been loaned to him in the days leading up to the killings.

McWright's involvement was evident a couple of hours before the bodies were found, when he arrived in a Nissan SUV and connected with Suggs at a gas station about 13 miles south of the farm field, according to the charges. A Dunn County sheriff's deputy detected what appeared to be blood on the ground where Suggs' Mercedes had been while at the gas station, the charges continued.

A court filing in Ramsey County puts Suggs and all four victims at the White Squirrel bar in St. Paul about 12 hours before the bodies were found.

Foreman met Sturm and Pettus at Shamrock's bar on W. 7th Street, where she and her half-brother worked, then they met up with Flug-Presley at the nearby White Squirrel bar, the Ramsey County court document said.

Suggs soon arrived in the Mercedes SUV, and one of the victim's phones was confirmed to be in Menomonie, Wis., not long before the bodies were found, the filing said.

"I spent the weekend mourning the victim's lives with their families, their friends, and our community members, and I feel in my soul how these senseless deaths shook our community to its core," St. Paul Police Chief Todd Axtell said in a statement. "We have four young lives — with all of their promise — erased. We have families left with only memories. And we have an entire community in search of answers."

The slaying claimed the largest number of victims in 23 years. In 1998, Khoua Her killed her six children in their St. Paul apartment. Her admitted to strangling them. Now 47, she has more than 10 years left to serve in prison and then another 16-plus years on supervised release.

In 1994, five young siblings were killed in the firebombing of a triplex apartment. Two suspects targeted the home of fellow gang member Andre Coppage in retaliation for cooperating with authorities in a murder case. Five of Coppage's siblings — brothers Nicheba, 11, Nicos, 7, and Niarte, 4, and his sisters Nikia, 8, and Myeka, 2 — died in the ensuing fire.

Robert Jefferson, 16 years old at the time of the crime, was convicted in federal court and is scheduled to remain in prison into his 60s. Half-brother Willie Hart pleaded guilty and was locked up for 10 years.

Last week's quadruple homicide pushes the city's total this year to 27.

"I'm proud of the work our investigators have put into the case — sleepless nights, days upon days at work, going home only to tuck their kids into bed and then returning to the office," the chief said. "I'm confident their dedication and unrelenting commitment to seeking justice for these four lost lives will soon provide the answers their loved ones so desperately seek."

Mayor Melvin Carter, in a statement, said that "losing Jasmine, Loyace, Matthew and Nitosha is one of the most heartbreaking traumas our community has ever endured."

The Minnesota Bureau of Criminal Apprehension, the FBI and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives are also working on the case. FBI spokesman Kevin Smith said his agency is providing supplementary assistance in what remains a state case.

"Our family has spent the last 25 years in this community, giving everything we knew how to give," said Jessica Foreman, Loyace's mother, fighting back tears during a vigil Sunday in St. Paul outside Mount Olivet Baptist Church. "And now we've given my baby."

Paul Walsh • 612-673-4482

Correction: Previous versions of this article misstated the most recent time St. Paul had a more deadly mass killing, due to incorrect information provided by police.