A mother of four was shot dead Tuesday morning outside her West Philadelphia home, in front of her young son as other children were on their way to school, according to relatives, friends, and neighbors of the victim.

Jennifer Fitzpatrick, 37, was the victim of domestic violence perpetrated by a "jilted ex-boyfriend," according to her father, 70, who declined to give his name.

"It's like a nightmare to me," said the father, adding that he had lost a son to gun violence. "I'm going to take it day by day."

Police had a man in custody Tuesday but did not release any information about the homicide on the 500 block of South Yewdall Street. Relatives of the victim said the man in custody was Anthony Alexander, who owns an auto-repair shop at 47th and Brown Streets.

Alexander and Fitzpatrick used to be in a relationship, and he is the father of her youngest child, a 4-year-old boy, relatives said. They said that Fitzpatrick recently broke up with Alexander and that Alexander "couldn't let her go."

Fitzpatrick obtained a restraining order Monday evening against Alexander, according to her family members.

About 8 a.m. Tuesday, the 4-year-old saw a gunman shoot his mother dead, relatives said.

"She was a beautiful mom who took care of her kids," said one of Fitzpatrick's cousins. "Nobody could say anything bad about her."

Neighbors said the deadly drama began at Yewdall Street and Cedar Avenue, near 54th Street.

Armed with a shotgun, the assailant was driving a black Mercedes-Benz. Fitzpatrick had dropped off two of her children at school in the morning and returned home to park near her house. When Fitzpatrick exited her vehicle, the gunman got out of the Mercedes and waved his shotgun, according to neighbors.

Fitzpatrick ran south across Cedar, then doubled back toward her home as the gunman ran after her, neighbors said. They said the gunman fired several shots during the chase. No one was hit by those shots.

Frightened children were running down the street to school as the chase was happening. The gunman reloaded, and Fitzpatrick screamed for help. He shot her dead at point-blank range in front of her house, got into the black Mercedes, and drove off, neighbors said.

The driver of the Mercedes was arrested at 47th and Brown not long after the shooting, according to residents of that area.

Police said information on the homicide would be released Wednesday.

Contact Sulaiman Abdur-Rahman at sabdur-rahman@phillynews.com, or follow on Twitter @sabdurr.