Latia Jones, a 21-year-old mother, was asked by her GED program to write an essay about her future.

She wanted to become a forensic psychologist so she could understand what motivates people to commit crimes and possibly help juveniles in trouble, she wrote. She described her own youth, of being sent to foster homes, group homes, and at least one juvenile facility. She also cited the "outrageous crime rates" in Philadelphia.

"Today it is May 1, 2012," she added, "and the homicide rate is 122."

Monday night, Jones and a 21-year-old male friend were added to that grim tally.

Police said Tuesday that they were looking into the possibility that the friend, Rodney Ramseur, may have been targeted in retaliation for his recent testimony in a 2010 homicide case or for his alleged criminal activity.

A $40,000 reward was being offered for the arrest and conviction of the person who gunned down the pair about 8:30 p.m. on the porch of Ramseur's home at the corner of Sparks and Third Streets in Olney, police said.

Ramseur's mother, Nicole Hyman, 42; his stepfather; his pregnant 18-year-old sister; and his 3-year-old brother were in the house at the time of the shooting. They were not injured.

Alvita Davis, 49, Jones' mother, said that if the two were killed because he cooperated in a criminal case and was not provided protection by authorities, then "somebody dropped the ball, and in the process of dropping the ball, it cost two lives."

Alyssa Ramseur, 23, Rodney Ramseur's sister, said her brother provided a "statement" in a case. She said the shooting was a shock to the family because no one believed he was in danger.

Homicide Capt. James Clark said Ramseur "was very well-known to police" but did not elaborate. Ramseur did not show up in a search of adult court records for Philadelphia.

Court records show Jones had an active bench warrant in a retail-theft case.

The shooter was described as a young black man in a gray hooded sweatshirt and dark blue jeans who was last seen running north on Third Street toward Godfrey Avenue. Police were seeking an older-model gray Ford Taurus with a black hood that may have been used in the slaying.

Clark urged anyone with information to call detectives at 215-686-3334.

Ramseur's sister said he graduated from Summit Academy, a reform school in Pittsburgh, and attended Millersville University to study business. He left after a year and began to pursue a career as a barber, and was in a program to help him get a barber's license, she said. "He wanted to open up his own barber shop, open his own business," she said.

Alyssa Ramseur said her brother had been dating Jones for a few months. Jones' mother, Davis, disputed that and said the two were just good friends.

Davis said she had planned to watch a movie on TV with her daughter Monday night at their home in the 6100 block of North Fourth Street near Third and Sparks when Jones announced she was going out.

"I'll be right back," Davis recalled her daughter saying. Naeem, Jones' 3-year-old son, remained with his grandmother.

A short time later, Davis got a call saying her daughter had been shot.

Contact Robert Moran at 215-854-5983 or bmoran@phillynews.com, or follow @RobertMoran215 on Twitter.