CLEVELAND - The day after Thanksgiving, Precious Smith says she and her fiancee, Damon Washington, known as "Paco", were having a quite afternoon until the mail arrived.

According to those inside the E. 72nd St. home, Ann Washington, 71, opened a letter from the Social Security Administration.

Ms. Washington's boyfriend, John Wagoner, was inside the home and says "Paco" become upset when his mother opened the letter.

"All of a sudden he just went off," said Wagoner.

"I don't know what was his problem."

The fight escalated and Cleveland Police say Ms. Washington picked up a steak knife and stabbed her only son in the chest, killing him. No one can believe it.

"That was just a mistake. she did everything she could," said Wagoner.

"I worry about her as much as I miss him," said Smith.

"I couldn't say that she did something intentionally like that, not to Paco."

Friends say Washington and her son were known to fight, but the arguments were usually brief and quickly resolved.

Wagoner says Ann took care of her son and was tired and frustrated after years of their volatile relationship.

"She tried to do everything she could for him," said Wagoner.

Now, as friends and family prepare to bury 33 year old Paco, everyone is trying to figure out what caused this 71-year-old woman, described as a "doting" mother, to stab and kill her only son.

"Everybody is just as shocked as I am I guess," said Smith.

Washington remains in the Cleveland City Jail.

She has not been charged.