THE LAST TIME Taylor saw her big brother, he was being his usual goofy self. Shakoor Arline had dropped the 17-year-old off outside her high school in Montgomery County, and she ran to get inside, darting up the steps.

But as she neared the door, Shakoor called out: "You're not going to give me a hug?" So Taylor ran back to the car to oblige her older brother, her protector, who left her with one final message:

"Good luck on your test today. I love you."

Carla, their aunt, choked back tears last night as she recounted the exchange, the last between the siblings.

Shakoor Arline, 25, and a companion, Lisa Smith, 32, were brutally slain Friday in what police called a "crime of passion" in Fairmount Park.

"Whoever did this took a bright light, a wonderful person who was a giving, loving human being, and erased him from the world for no reason," his aunt said.

"That person has left behind a little sister who looked up to him, a void that she will never, ever get rid of," added Carla, whose last name is being withheld by the Daily News at her request.

Yesterday, investigators provided more information about their probe of the murders. Workers from the city's Department of Parks and Recreation had found the pair Friday afternoon, each shot several times in the head, in the back seat of Smith's Toyota Sequoia.

Smith and Arline were killed during a sexual encounter and were found partially clothed, according to Homicide Capt. James Clark.

The victims had parked the SUV in a secluded section of Fairmount Park near Lemon Hill Mansion between Boathouse Row and Fairmount. It was a spot, Clark said, that the two had visited before.

They were in the back seat sometime early Friday when someone walked up, opened the back door, reached in and fired several shots, then fled.

"I can tell you from the crime scene it appears to be very much a crime of passion," Clark said. "We've got nine shots fired, all of them head shots." He noted that neither victim had a criminal record.

Arline and Smith had met at work and had been involved romantically off and on for several years, Clark said. Both were in relationships with other people.

Clark added that police were seeking to speak with a man who was romantically involved with Smith.

Smith, a mother of five, grew up in Northeast Philly but was originally from Arizona, a close friend said last night.

As a teen, she lived with her father's parents and attended Northeast High School. Her mother, who is in ailing health, still lives in Arizona, and Smith often made the trek to visit her, said the friend, who didn't want to be identified.

Smith's SUV bears Arizona tags, although she lived on Oakland Street near Levick in Oxford Circle.

Clark did not say the man who was in a relationship with Smith is a "person of interest" in the case, but acknowledged that investigators were focusing on him.

Police sources said last night that detectives believe the killer may have been watching Smith and tailed her to Arline's house, about a half-mile from Lemon Hill.

Detectives also interviewed a woman who was in a relationship with Arline, Clark said, but he did not describe her as a suspect.

Arline lived on Girard Avenue near 28th Street in Fairmount with his grandmother and younger brother, Justin, his aunt said last night.

He was "the man of the house," and made sure everything was taken care of.

"I only think of his smile, and how loving he was to his sister and mother," Carla said. "And how much we're all going to miss him."

Her father broke the news to her Friday night, after receiving a call from her brother, who had been married to Arline's mother for 10 years.

The family had been frantically trying to reach him since Friday morning, when they were told he hadn't shown up for work.

"I just lost it," she said. "I still can't really understand it."

Memories have been flooding back: Of Arline as a goofy, nerdy kid who loved to pester his younger siblings. Of him maturing into a cooler, more confident adult who wanted to turn his passion for cars into a career.

Like Smith, Arline grew up in Philly. He spent about five years in rural Virginia, his aunt said.

He graduated from Edward W. Bok Technical High School and worked for a time at UPS. In more recent years, he had been working as a mechanic.

"He was a sweetheart, just the nicest kid ever," Carla said. "He did nothing to deserve this."

Anyone with information on the slayings is asked to call detectives at 215-686-3334 or -3335.

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