SHYEMA Washington had one person on her mind Saturday night as she stumbled back into her 3-year-old niece's birthday party with blood pouring out of her mouth.

"She wanted her son," said Washington's sister, Daneesha Hill. "She just kept asking me about him."

Hill said yesterday afternoon that she might not have the strength to answer her little sister's question if and when she regains consciousness.

Tyrell Styles, Washington's longtime boyfriend, not only shot Washington in the mouth, but also shot and killed their 5-year-old son, Cion Styles, according to police.

"She does not know what happened to her son as of yet," Ridley Township Police Lt. Scott Willoughby said of Washington, 26, who was in critical condition at Crozer-Chester Medical Center yesterday, following the shooting at 11 p.m. Saturday outside Hill's apartment in the township's Crum Lynne section.

"I don't want to be the one to do it," Hill said. "Me being a mom, I just couldn't imagine."

Washington, a certified nursing assistant from West Oak Lane, remained conscious long enough to tell the first officer on the scene that Styles had shot her. She was struck in the mouth, buttocks and midsection, police said.

Styles, 26, then turned the 9 mm Ruger handgun on Cion and fired a round into his forehead, according to police. The boy, also shot in the ankle, dropped to the grass and was pronounced dead soon afterward at the hospital.

"He went to his cousin's birthday party and he ended up with two gunshot wounds," Willoughby said. "He ended up dead."

Police say Styles took off in his white Pontiac Gran Prix and blew through red lights on Chester Pike, heading in the direction of Philadelphia. After striking two vehicles, he came to a dead end in Sharon Hill, where he put the gun to his head and pulled the trigger.

"As they exited their patrol cars, they heard a single gunshot from the vehicle," Willoughby said of the cops.

Styles is brain-dead and was on life support yesterday at the Hospital of the University of Pennsylvania, Willoughby said.

Meanwhile, Hill, 29, was still trying to make sense of what happened behind her apartment Saturday night. She said that Styles, who recently had broken up with Washington, was dropping Cion off at the party after spending a few hours with him earlier in the evening. She didn't hear an argument before the shooting.

"It just seems like a nightmare," Hill said. "That's my little sister. That was my nephew. She's in critical condition. He's gone."

Hill said that Styles, a security guard, had "put his hands on" Washington before, and that Washington had once sprayed him with Mace. But he didn't seem violent in person, Hill said. A photo from less than two months ago shows Washington and Styles smiling and dancing together at Hill's wedding.

"The stories she told me didn't match up with what I saw. He had two personalities," Hill said.

"He was a little guy," she added. "I don't think she thought he was a threat."

Saturday's birthday party was for Hill's daughter, Summer, who turned 3 years old. She was still awake when Styles opened fire, and witnessed the aftermath, Hill said.

Summer didn't mention the shooting yesterday, but has remained close by her mother, occasionally chiming in on her conversations or requesting a back scratch. Hill is concerned that what she saw on her 3rd birthday will have psychological repercussions down the line.

"She's old enough to know things," Hill said. "She saw everything. She's eventually going to ask something."