A Philadelphia man charged Monday in connection with the vicious murder of a Delaware County woman in September is linked to a string of brutal sexual assaults and another murder in Kensington, authorities say.

Byron Shamor Allen, 37, of the 1800 block of 73rd St. is charged with first-degree murder, robbery and other charges in the killing of Natasha Gibson, 32, of Yeadon. Gibson was mother of a 10-year-old daughter.

Allen, who was already in custody in connection with a sexual assault in Philadelphia, was remanded to Delaware County jail after his arraignment, officials said.

"Make no mistake, we don't believe that the motive for this particular murder was robbery," said Delaware County District Attorney Jack Whelan. "This is a callous, brutal, heinous crime. It is a devastating murder."

On a mild Thursday night in late September, Gibson had just left Dan's Corner Tavern in Upper Darby and was walking to meet up with a friend in Yeadon when she caught the eye of Allen.

Allen, who has a violent criminal history, followed Gibson along the darkened streets. He caught up with Gibson and brutally stabbed her more than 20 times in the chest, neck and head, authorities said.

When police arrived they found Gibson, the mother of a 10-year-old girl, dead on the concrete steps of her friend's apartment. A trail of blood led away from the scene.

A police K-9 was brought in and followed the blood trail from the scene through Yeadon, Upper Darby, and into West Philadelphia before the dog found a bloody steak knife used in the killing located in a storm drain in the Cobbs Creek area.

Yeadon detectives had located nearby surveillance video showing Allen in a baseball cap.

Then they located a second surveillance video. That video was taken at a convenience store in the 5800 block of Catharine Street where Allen stopped on his way home. The video shows Allen hiking up his pants and then reaching into the refrigerator case for a Steel Reserve beer – his hand bleeding from a wound he incurred during the murder, authorities said.  He was also missing the tip of his right index finger from a previous unrelated injury.

Police found Gibson's identification in a nearby sewer inlet and her purse along a fence at 6250 Baltimore Ave.

Police initially questioned another man but released him after an interview, saying he was no longer a suspect.

Authorities do not believe Allen had any previous encounter with Gibson.

Natasha Gibson knew how cheer up friends and family when they were having a bad day and bring a smile to their faces.

"She glowed!" her family wrote about her on a GoFundMe page set up to defray her funeral expenses.

But authorities say Allen left another grim trail in his wake.

Philadelphia police had been investigating a string of assaults in the Kensington area since April. On Oct. 11, Philadelphia police concluded Allen was a suspect in four sexual assaults. He was arrested two days later.

In Philadelphia, Allen was often seen riding a mountain bike. He would approach prostitutes working in a known high drug crime area, authorities said.  He would lead the victims to a second location, where the attacks would occur, said Det. Jim Owens, Philadelphia Police.

The first attack occurred April 19, when a 45-year-old woman was repeatedly stabbed in the throat with a box cutter near Braddock and Toronto Streets.

Three more sexual assaults that have now been linked to Allen. They took place July 12 on the 3800 block of Jasper Street, in late July on the 3100 block of Jasper Street and on Oct. 1 on the 2700 block of Ruth Street.

DNA evidence from the Oct. 1 assault that led police to Allen.

"His profile came off that," said Owens.

Allen is also the "prime suspect" in murder of Rickie Morgan, who was killed in July, said Capt. Mark Burgmann, Philadelphia Police.

Police officers found Morgan lying naked on the sidewalk, covered in blood from head to toe, on the 2400 block of Jasper Street on July 16 at about 11:20 p.m. Medics pronounced her dead at the scene.

Morgan had been stabbed and beaten with a brick. She initially escaped and ran from the scene but collapsed and died.

Whelan said Allen had a previous criminal history that stretches back years.

He was arrested in Philadelphia for a 1996 robbery and served time, Whelan said.

In March 2002 Allen, while high on drugs, stood on the hood of a Nissan Stanza parked outside the 601 Bar at 56th and Wyalusing and fired several times from a shotgun, hitting three men that had allegedly argued with his mother and tried to shoot her the night before, according to news reports.

Allen and an accomplice then car-jacked a Pontiac Bonneville from a 61-year-old man. The two were later wounded in a gun-battle with police. Allen was charged with attempted homicide and sentenced to nine to 19 years in prison.

"He was released in 2015 and he started a brand new crime spree," said Whelan.