A deranged felon allegedly stabbed a mother of three to death and left her body in a gas station parking lot. 

Michael McHenry, 40, was arrested and charged with second-degree murder after he allegedly fatally knifed his girlfriend, Juliann Bachmann, 30, on Saturday morning, prosecutors stated.

Police responded to a 911 call and found her body in a parked car at a Speedway in Yaphank just before 7.30am.

First responders rushed the mother to NYU Langone Hospital in Patchogue, where she was later pronounced dead. 

Later that night, Suffolk County Police arrested McHenry in connection with her death.

The alleged killer was taken into custody just after 8pm and held overnight in jail ahead of a Sunday arraignment. 

The ex-con was on probation and was armed with a knife, according to a criminal complaint obtained by the NY Post.

McHenry allegedly stabbed Bachmann in the neck and chest, per the complaint.

He allegedly attacked her in her car and on the ground after he dragged her out, the complaint stated.

Horrified bystanders told police they dialed 911 during the vicious assault, but McHenry allegedly fled the scene before authorities arrived. 

McHenry is now ordered to be held without bail.

Bachmann's grief-stricken father sobbed in court as McHenry made faces and glared at the family during his arraignment on Sunday, according to the New York Post.

Tributes for the mother of three flooded Facebook following news of her tragic death. 

'When I got that call I thought I was having a heart attack,' one person wrote on Facebook.

'You did not deserve this you was high spirit always joking you will be so missed fly high with the angels.'

Another person wrote: 'People are so cruel and evil. You had a beautiful heart, may god watch over those beautiful babies you left behind.'