A St. Louis-area suspected serial killer has been charged in two murders and could be tied to four homicides and two shootings across two states, authorities said Monday. 

Perez Deshay Reed, 25, of Bellefontaine Neighbors, 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 believed to have killed 16-year-old Marnay Haynes on Sept. 13 and 40-year-old Lester Robinson on Sept. 26. 

Reed has denied hurting anyone, according to court documents. 

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This undated photo provided by St. Louis County Justice Services shows Perez Reed, who was charged Saturday in the shooting deaths of 16-year-old Marnay Haynes on Sept. 13 and 40-year-old Lester Robinson on Sept. 26. Police are trying to determine if he was involved in at least four other homicides in Missouri and Kansas. (St. Louis County Justice Services via AP)

This undated photo provided by St. Louis County Justice Services shows Perez Reed, who was charged Saturday in the shooting deaths of 16-year-old Marnay Haynes on Sept. 13 and 40-year-old Lester Robinson on Sept. 26. Police are trying to determine if he was involved in at least four other homicides in Missouri and Kansas. (St. Louis County Justice Services via AP)

"The cases in the City of St. Louis are currently under investigation to ensure the most important goal – that justice is brought to the many victims and their families; and the person responsible is held accountable for these heinous crimes," St. Louis Circuit Attorney Kim Gardner said in a statement. 

Police are investigating whether or not Reed killed Damon Irvin, 35, and Daja Fairrow, 25, 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.

The killer's motive remains unknown but most of the victims were women, authorities said in court documents. Investigators do not believe the victims knew each other or their assailant. Within days of the shootings, authorities issued an alert warning that a gunman was targeting sex workers.

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"These seem to be random acts," St. Louis County Police Lt. Craig Longworth said. "Why? I can't give an answer to that."

Authorities talk to reporters on Monday about charges filed against Perez Reed in St. Louis. 

Authorities talk to reporters on Monday about charges filed against Perez Reed in St. Louis.  (St. Louis Metropolitan Police Department )

The FBI arrested Reed over the weekend while he was traveling from Kansas City, Kansas, to St. Louis. He was in possession of a .40-Caliber handgun that matched shell casings found at the scene of at least three of the killings, the FBI said. 

The weapon also matched casings found at the scene of several murders in St. Louis, investigators said. 

"We got a violent offender off of the streets and without the cooperation that would not have gotten done," said St. Louis County Prosecuting Attorney Wesley Bell during a news conference. 

The case began to come together when authorities in Kansas City contacted their St. Louis counterparts after the two murders in their jurisdiction and they passed off information on Reed, whom they suspected of being involved, authorities said. 

A St. Louis Metropolitan Police Department vehicle. 

A St. Louis Metropolitan Police Department vehicle.  (St. Louis Metropolitan Police Department )

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The FBI said that on Friday, officers were watching Reed when he got on an Amtrak train from Kansas City bound for St. Louis. He got off at the first stop, in Independence, and was getting on a bus when he was taken into custody.

Authorities declined to label Reed a possible serial killer but the FBI defines serial murder as the unlawful killing of two or more victims by the same offender in separate events. 

The Associated Press contributed to this report.