The Milwaukee Police Department has five people in custody after a succession of violent acts left a mother, her two sons and another woman dead at the end of last week.

Rachel Thompson, 23, Torian Thompson-Carter, 4, and Jaden Thompson-Carter, 3, were found inside their South Side duplex after firefighters extinguished a small fire in the home located in the 800 block of South 12th Street.

Milwaukee Police Chief Edward A. Flynn said officials believe foul play caused the fire.

“We believe that fire was indeed set to cover up the crime scene,” Flynn said during a press conference Sunday.

Flynn said MPD is not commenting on how Thompson and her two sons died.

“Those details are known to their killers,” Flynn said. “If we speculate or report on those details, that could compromise any statements that we might subsequently procure from suspects.”

Upon investigation, MPD discovered two of the duplex residents were not among the dead. Thompson’s 6-week-old son and 19-year-old friend living in the duplex were both missing.

The infant, Maurice Visor Jr., was found unharmed Friday afternoon in a baby carrier on the steps of a church eight miles from the duplex.

Police later found Thompson’s friend and roommate, Brittney Robertson, Friday evening outside a residence on Milwaukee’s northwest side. Robertson died from a gunshot wound.

Police believe Robertson was involved in the death of Thompson and her children. At this time, officials do not know if Robertson took the baby from the duplex or why her body was found far from her home.

“We certainly believe she was involved in the homicide and we are investigating those avenues,” Flynn said. “Who specifically took whom where will clearly be information developed as the investigation continues.”

As of Monday, MPD has placed five people into custody in connection with the murders. The arrests were made over the last two days.

Flynn said the suspects are being questioned to determine their involvement in the murders and what charges will be filed. He would not comment on how officers were led to the suspects.

“Much of this will come out once we’ve done the formal charges and make a presentation with the district attorney’s office,” Flynn said. “So at this point in time, we cannot go into too much detail as to how we identified these individuals.”

Flynn said the suspects are individuals who were associated with Robertson. However, their relationship to Thompson is currently unknown.