Happy but still sad

A young Queens woman was killed by a party crasher who fired shots through a closed door after she helped toss him from the bash Sunday, cops and her family said.

Police announced the arrest of the suspected murderer early Monday.

The victim, Avalisa Morris, 26, had planned the surprise party in St. Albans for a close friend’s birthday. She spent all day Saturday cooking Caribbean food for the special occasion, her stunned family said.

“She was a people pleaser,” said her great-uncle, Spencer Grant. “She was in the act of doing something kind and suffered a senseless death.”

The man who crashed the party at a two-story home on 119th Road came to see a female guest over a previous dispute, police and Morris’ family said.

O’neil Mairs, 23, of Springfield Gardens, Queens, was kicked out and had a basement door locked behind him shortly before 4:30 a.m. Morris was the one who made sure he and others involved in the argument didn’t get back inside.

“She was at the door, and the people that were fighting went outside,” said her cousin, Larrissa Whyte, who was at the party.

“And she closed the door, and she was standing by the door to make sure that they didn’t come back in.”

Furious over getting the boot, Mairs ruthlessly fired at least two rounds through the closed door, cops said. Morris was hit in the head and the abdomen, police said. She fell to the floor and died.

Whyte, who helped Morris plan the party, was upstairs when the gunfire set off pandemonium in the basement.

“Everybody ran up the stairs to come out the front door,” Whyte told the Daily News outside the party as detectives investigated her cousin’s murder.

“I was looking for her, and somebody said she got shot. So I went downstairs.”

Whyte broke down in tears as she recalled finding her mortally wounded cousin lying on the floor, just inside the basement door.

The killer fled the scene. But cops later arrested Mairs  and charged him with murder, criminal possession of a weapon and reckless endangerment.

Morris’ loved ones grieved at a family home in Springfield Gardens. Grant, Morris’ great-uncle, described her as “so friendly and so, so courteous.”

“Every time I seen her, it was always a hug and a smile,” he said. “I never saw her angry.”

Morris worked as a personal banker at a Capitol One branch in Queens. She was born in Jamaica and came to the U.S. a dozen years ago. The party was for a friend who worked at the Macy’s in Green Acres Mall in Valley Stream, L.I.

“She cooked all day,” said Morris’ aunt Audrelyn Anderson, remembering how Morris spent Saturday cooking for the party. She made Caribbean dishes like oxtail, goat, and rice and peas.

Morris’ mother went into seclusion yesterday after the murder of her only child, relatives said. And Morris’ cousin, Whyte, was inconsolable.

“They’re just like twins. They were always together,” Grant said. “Since she came home, she’s been in bed.”