A man going through a divorce stabbed his mother-in-law to death, wounded his teen brother-in-law – then slit his own wrists and set their Queens home on fire on Thursday, cops and sources said.

The 27-year-old man allegedly knifed his 50-year-old mother-in-law and her 17-year-old son multiple times inside a house on Smart Street near 45th Avenue in Flushing just before 4 p.m., authorities and sources said.

The unhinged rampage occurred in the Flushing section of Queens on Tuesday. Brigitte Stelzer

The victims were taken to NewYork Presbyterian Hospital, where the gravely wounded mother-in-law succumbed to her injuries and the teen was listed in stable condition.

The alleged attacker was also hospitalized and placed in police custody, according to the sources.

A dozen FDNY and EMS pe

See Full Page