A 69-year-old Florida man was arrested last week after allegedly planning to carry out a mass shooting at a Florida mosque, authorities announced Monday.

Jacksonville Sheriff Mike Williams said his office received a tip in late October that Bernandino Bolatete had expressed “strong anti-Islamic sentiment” and planned a mass shooting at the Islamic Center of Northeast Florida. An undercover detective began speaking to Bolatete and other state and federal agencies began to take steps to prevent an attack.

According to court records, the detective became friendly with Bolatete, a Philippine national who has a green card, at a local shooting range. Bolatete confessed his failing health — the result of being shot in the kidney by a police officer in the Philippines years ago. Bolatete claimed to have killed the officer who shot him, court records said, and he also described his own prowess with firearms.

In one conversation, the detective and Bolatete drove past the mosque on their way to the firing range. Bolatete said he expected bad news about his remaining kidney at an upcoming doctor’s appointment and would then go to the mosque to kill worshippers, according to a transcript of the conversation in court documents: