Upper Darby, Pa. -

A 20-year-old Drexel Hill radio dispatcher for the Pennsylvania State Police was allegedly killed by her estranged boyfriend last night as her 13-year-old sister hid in a closet frantically calling their father and police.

Amber Jackson had broken off her relationship with Freddie Cleveland on Sunday and moved back in with her parents on the 400 block of Foss Avenue in Drexel Hill, said Upper Darby police superintendent Michael Chitwood.

Jackson arrived home at 5:30 p.m. last night Cleveland was outside the house.

"He was laying in wait for her," Chitwood said.

The former lovers argued on the front steps. Jackson managed to slip inside and locked a plate glass door behind her.

Cleveland kicked it in, and followed her into the house.

Jackson ordered her 13-year-old sister to hide in a closet as the man chased her up the stairs to a second floor bathroom.

With a 14-inch kitchen knife in his hand, he repeatedly attacked his former girlfriend.

"There were so many stab wounds that our people lost count," Chitwood said.

Police arrived minutes later and found Jackson dead at the scene.

Cleveland, a sanitation worker for Lansdowne Borough, was discovered unconscious in the kitchen with at least one stab wound to his chest.

Taken to the Hospital of the University of Pennsylvania, Cleveland was in critical condition in a medically-induced coma this morning but expected to live, Chitwood said.

"We're still investigating how he got his wound, whether it was self-inflicted" or incurred during the assault on the woman, Chitwood said.

Jackson's 13-year-old sister was not injured.

"It's really sad," Chitwood said this morning. "The victim was trying to do everything right with her family. Her last act was trying to save her sister."

Contact staff writer Sam Wood at 215-854-2796 or at samwood@phillynews.com.