By: Najla Alexander
Authorities in Somerset County announced that on Friday, March 28, defendants Thomas Kaiser and Erich Kaiser entered guilty pleas before the Honorable Angela F. Borkowski, J.S.C., in connection with severe injuries and extensive property damage caused by the defendants’ detonation of a homemade explosive device at Cooper Street Park in Manville, on July 6, 2024.
According to Somerset County officials, defendant Thomas Kaiser, 60, of South Plainfield, pleaded guilty to second degree Causing or Risking Widespread Injury or Damage, fourth degree Aggravated Assault by recklessly causing bodily injury with a deadly weapon, and third degree Criminal Mischief.
Defendant Erich Kaiser, 29, of Monmouth Junction, pleaded guilty to fourth degree Aggravated Assault by recklessly causing bodily injury with a deadly weapon, and third degree Criminal Mischief, Somerset County authorities stated.
The guilty plea exposes defendant Thomas Kaiser to a 6-year prison term.
Somerset County officials say defendant Erich Kaiser faces a period of probation with a suspended term of 180 days in county jail. Defendants must also pay restitution to the victims. Sentencing is scheduled for May 23.
According to SCPO officials, at about 8:16 p.m. on July 6, 2024, police and emergency medical personnel responded to Cooper Street Park in Manville for a reported explosion that severely injured a 34-year-old male victim and caused damage to multiple homes and vehicles.
The investigation revealed that defendant Thomas Kaiser brought a homemade explosive device, essentially a metal tube containing explosive powder, to the area of Cooper Street Park, SCPO officials said.
Defendant Erich Kaiser placed the device in an empty area of the park and ignited the fuse, Somerset County authorities said. The powerful explosion caused multiple shards of the metal tube to be sent flying off in various directions.
One shard struck a male victim. Other shards pierced through the outside and inside walls of multiple homes and caused damage to vehicles, according to Somerset County officials. 
Somerset County officials stated that the investigation was conducted by the Manville Borough Police Department, the New Jersey State Police Bomb Squad, and the Federal Bureau of Alcohol, Tobacco, Firearms and Explosives.