Yeshiva Mikdash Melech in Brooklyn recently received a threatening letter, allegedly sent by inmate Matthew Karelefsky, 47, who is currently serving a 25-years-to-life sentence for attempted murder and arson.

The letter, addressed to the yeshiva on Ocean Parkway in Midwood, warned of planned mass shootings in three zip codes: 11230 and 11210 in Brooklyn, and 06710 in Waterbury, Connecticut.

Karelefsky was convicted in 2024 for setting fire to a longtime Chaim Berlin rebbi’s home in 2019, an attack that injured 13 people, including a 6-week-old infant.