ST. LOUIS (NewsNation Now) — The FBI said a suspected serial killer has been arrested after allegedly shooting at least six victims in Missouri and Kansas.

The FBI said Perez Reed, 25, shot the victims with the same .40 caliber gun. Four of the victims died from their wounds.

The St. Louis County man was arrested while coming back to the city over the weekend. He was taken into custody while traveling by train from Kansas City back to St. Louis at a stop in Independence, Missouri. He had the gun in his possession, according to authorities.

Reed was charged Saturday with two counts of first-degree murder, three counts of armed criminal action and one count of first-degree assault.

He is suspected of killing a 16-year-old girl, Marnay Haynes, on Sept. 13, and also suspected in the fatal shooting of 40-year-old Lester Robinson on Sept. 26. He is also accused of a third shooting in St. Louis County that left a person with permanent disabilities.

The St. Louis Post-Dispatch, citing a police affidavit filed in federal court, said Reed could be tied to at least four other homicides and additional shootings. Among them, police are investigating whether Reed killed Damon Irvin and Daja Fairrow, whose bodies were found earlier this month in an apartment complex in Kansas City, Kansas. Charges have not been filed in those killings.

Meanwhile, St. Louis city police said Monday that they plan to seek charges against Reed in the recent shooting deaths of 49-year-old Pamela Abercrombie and 24-year-old Casey Ross.

Investigators say Reed shot some of the victims in the same “distinctive manner.” There does not appear to be any connection between the victims.

Authorities have not provided a motive for the shootings.

Reed, in an interview with police, denied hurting anyone, the affidavit stated.

The Associated Press and NewsNation affiliate KTVI contributed to this report.