THE PHONE call that Betty Ellington had been hoping to receive for almost a month finally came a little after 7 yesterday morning.

The voice on the other end belonged to a Philadelphia homicide detective, who told the 79-year-old that investigators had locked up the man who killedher son, Wayne Ellington Sr., last month.

"I had faith that they would catch him," she said. "The detectives had promised me that they would."

Homicide Capt. James Clark said Carl White, 34, was arrested early yesterday and charged with fatally shooting Ellington, 57, the father of Los Angeles Lakers guard Wayne Ellington Jr., on Marion Street near Hansberry in Germantown on Nov. 9.

Police said the motive was an argument. Ellington was found inside his Oldsmobile with a gunshot wound to the left side of his head.

Homicide detectives were led to White, of Green Street near Preston, by his probation officer, who notified investigators this week that White hadn't checked in, Clark told the Daily News.

Court records show White's most recent brush with the law was in 2011, when he received 12 months' probation on drug charges.

Those detectives tracked White to a halfway house in the area of B and Erie streets in North Philadelphia, Clark said, and took him into custody.

Clark said White is "extremely well-known to police" and has a violent arrest record. The Powelton resident has had convictions for firearms violations and assault, as well as numerous drug offenses, court records show.

Investigators also are probing White's potential involvement in other, unrelated shootings, Clark said.

Betty Ellington said her family is still reeling from the slaying of her son.

"This is a sad time in our lives. I'm devastated over his death," she said. "I'm happy that they found the [suspect] and got him off the streets, but it don't bring my son back."

Wayne Ellington Sr. had worked in finance in Bensalem, and had two adult daughters and two grandchildren.

He wasn't shy about voicing his pride for his 27-year-old son, and devoutly followed Ellington Jr.'s NBA adventures either on TV or in person.

Betty Ellington said she called her grandson as soon as she got off the phone with investigators yesterday morning.

"I told him he's got to play for his dad now," she said. "He was his No. 1 fan."