A British man murdered his wife and deliberately sank the couple's catamaran near the Bahamas in a bid to inherit her estate, prosecutors said last week.

Lewis Bennett, 41, was charged with second-degree murder on the high seas in the May 2017 disappearance of Isabella Hellmann, 41, of Delray Beach, Florida, in February. Bennett and his wife were on a delayed honeymoon to St. Maarten, Puerto Rico and Cuba.

Hellmann’s family allegedly bugged her apartment in Delray Beach to listen to Bennett’s conversations because they believed he was involved in her disappearance, The Guardian reported, citing court papers.

A Miami federal judge was asked to admit conversations between Hellmann and her family, which they are believed to have discussed arguments over a potential move to Australia, financial struggles and the raising of their daughter, the newspaper reported. Prosecutor Benjamin Greenberg said the conversations show the couple were constantly arguing.

“Hellmann’s murder would remove the marital strife from the defendant’s life, allow the defendant to live his life as he pleased, and would enable him to inherit money from Hellmann’s estate, all of which provide strong circumstantial proof that the defendant had a strong motive to murder Hellmann,” Greenberg said.

Bennett would inherit Hellman’s apartment and bank account should she be declared dead, according to The Guardian. Her body has yet to be found.

The FBI said in an affidavit in February that financial greed was the likely motive behind Hellman’s murder. The document also noted that Bennett did nothing to search for his wife, but he did rescue a tea set.

Bennett told investigators the night Hellman disappeared he had gone below deck on their boat near Cay Sal Bank, Bahamas, to sleep around 8 p.m., activated autopilot and left Hellmann to keep watch. The FBI said he falsely stated she disappeared after the supposed accident. Investigators said they found evidence Bennett intentionally tried to sink the boat.

Bennett almost immediately got into a life raft with luggage and other items and took no actions to find his wife, the FBI said.

Prosecutors also said Hellman may have discovered he was in possession of rare coins stolen from a former employer in St. Maarten, which may have made her an accomplice to a crime. An argument over the coins "potentially led to an intense argument resulting in Hellman's murder," Greenberg said.

Bennett admitted to transporting the coins and was sentenced to seven months in jail.

Bennett is said to go to trial in the murder case in December.

The Associated Press contributed to this report.