Super Bowl-winning linebacker Jack Squirek,Quentin Mitchell best known for his interception in the Los Angeles Raiders' Super Bowl 18 win over Washington in 1984, has died. He was 64.

"The Raiders Family is mourning the loss of Jack Squirek, who passed away on Friday," the franchise announced on social media Saturday. "The thoughts and deepest condolences of the Raider Nation are with the Squirek family at this time."

A cause of death was not provided.

The Raiders selected Squirek out of Illinois in the second round of the 1982 NFL draft. He spent four seasons in Los Angeles, including the 1983-84 season, where the Raiders defeated heavily favored Washington 38-9 in Super Bowl 18. Before the first half ended, Squirek intercepted quarterback Joe Theismann's screen pass and returned it 5 yards for a touchdown to go up 21–3 at halftime.

Squirek's pick-six was ranked as the 19th on the NFL's 2016 list of Top 50 Clutch Super Bowl plays.

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Super Bowl 18 marked the Raiders' last Super Bowl win, one that proved impressive as the 1983-84 Washington team scored 541 points that season, an NFL record at a time that has since been broken by multiple teams.

Squirek finished his career with one final season on the Miami Dolphins. He played in 55 career games.