LONDON (AP) A British doctor on Monday admitted trying to kill his mothers long-term partner, who stood between him and an inheritance, by injecting the man with poison disguised as a COVID-19 vaccine.

Prosecutors say Thomas Kwan pretended to be a community nurse delivering booster shots and injected Patrick OHara with a toxic substance, likely a pesticide. OHara, 72, developed a rare flesh-eating disease that left him in intensive care.

Kwan, 53, initially denied attempted murder but changed his plea to guilty after prosecutors laid out their case at Newcastle Crown Court in northeast England.

Prosecutor Thomas Makepeace told the court that Kwan was a respected and experienced family doctor based in Sunderland, about 15 miles from Newcastle. The lawyer said Kwan used his encyclopedic knowledge of poisons in his plot to kill OHara, who was a potential impediment to Mr. Kwan inheriting his mothers estate upon her death.

Makepeace said Kwan forged documentation, used a vehicle with fake license plates and disguised himself with head-to-toe protective clothing, tinted glasses and a surgical mask to visit the home in Newcastle that OHara shared with Kwans mother, Jenny Leung, in January.

As I suspect, would any of us, Mr. OHara fell for it hook, line and sinker, the prosecutor said.