York residents charged in stabbing murder of York man in Florida

Emilio Sifuenties Jack. Photo courtesy of the Bay County Sheriff's Office.

Two York residents are charged in the murder of a York man in Florida over the weekend.

Bay County Sheriff's Office said in a news release that Emilio Sifuenties Jack, 28, killed Mark Thomas Jankiewicz, 25, by stabbing him with a screwdriver on Friday, July 26. The alleged stabbing occurred in Panama City, police said. 

Kayle Marie Kostick, 23, was with Jack at the time and handed him the murder weapon, according to authorities.

Jankiewicz's body was found about 1:15 p.m. Saturday, July 27, near a boat ramp on the Hathaway bridge. He had puncture wounds to his neck, according to authorities.

Officials said Jankiewicz had been released from Bay County Jail earlier Friday and was with Jack and Kostick that night.

Police arrested the two, and initially Kostick gave what authorities said was a rehearsed statement. 

Eventually, police said, she told them the three had been driving around before going to the boat ramp.

There, Jack suddenly started choking Jankiewicz, the release states. Police said Jack pulled a screwdriver out but fumbled it, and he asked Kostick to give it to him.

She handed it to him, and Jack proceeded to stab Jankiewicz in the neck with it, the release states.

Kostick told authorities that Jack used a second screwdriver to stab Jankiewicz, according to police.

After that, Jankiewicz's body was wrapped in a blanket and left by a picnic table, the release states.

The blanket, police said, had been in Jankiewicz's truck, which Kostick and Jack were seen driving.

Jack threw the screwdrivers into the bay nearby, authorities said, but a dive team was able to locate them.

Police said the motive for the murder is not known but that it is believed that drugs and alcohol were involved.

Jack was uncooperative with authorities, according to the release.

Kostick is charged with principal to premeditated murder, and Jack is charged with murder. The two were sent to Bay County Jail.

— Reach Christopher Dornblaser at cdornblaser@yorkdispatch.com or on Twitter at @YDDornblaser.