A St. Paul man fatally stabbed his wife's friend in the heart after she tried to help the woman leave, according to a murder charge filed Thursday.

Htoo Day, 61, of St. Paul, allegedly killed Paw Boh Htoo about 4:53 p.m. Tuesday in an apartment complex in the 100 block of Edmund Avenue. He was charged in Ramsey County District Court with one count of second-degree murder with intent.

Paw Boh Htoo, 29, of St. Paul, died of a single stab wound to the heart.

According to the complaint: the oldest two of Htoo Day's four children, who range in age from 4 to 12, broke a mirror in the family's apartment on Sunday while "horsing around." He kicked the children out, and his wife left with them. The wife and children stayed with a friend in the same apartment building.

Paw Boh Htoo arrived at the friend's apartment on Tuesday to interpret mail for the woman, who divulged the couple's problems and expressed a desire to move in with relatives.

"[Paw Boh Htoo] agreed to assist her toward that end," the complaint said.

The woman returned to the couple's apartment to retrieve their youngest child. Htoo Day told her to stay, grabbed her and placed her in a bear hug, the complaint said.

The woman broke free and returned to the friend's apartment with her youngest child. Htoo Day followed, allegedly threatened to kill her and her family and produced a large knife from a shoulder bag.

Htoo Day confronted Htoo in the apartment. She informed him that she would help his wife leave if she wanted to. Several witnesses told police that they then saw Htoo Day stab Paw Boh Htoo.

Htoo Day allegedly admitted to the stabbing in a police interview, and said he was "angry and drunk," the complaint said.