ST. LOUIS – A St. Louis man admitted to harassing and threatening to rape five women in a federal court hearing Thursday.

Robert D. Merkle, 54, pleaded guilty to five federal felonies, which includes two counts of interstate communication of threats and three counts of cyberstalking.

According to his plea, Merkle admitted to harassing women in the St. Louis area and across the country for several months, while he was on parole for similar crimes with different victims.

The federal investigation into Merkle’s threats began in January 2022, when a woman told the Town and Country Police Department that a man she’d met on a dating site more than seven years earlier sent a series of suspicious text messages. The messages hinted that he had made a copy of her house key and was planning to enter her home two days later and rape her.

The FBI obtained a court-approved search warrant for Merkle’s home and cell phones. Investigators determined he had used emails, multiple cell phones and a service that can send texts anonymously to harass women.

Investigators say Merkle met several women who he threatened through dating sites and worked with another woman in contacting them. A sentencing hearing is planned for June 21 after Thursday’s plea. Merkle could be sentenced up to five years in prison for the threats.

Merkle was also charged with harassment from 2017-2018 in St. Louis and Jefferson counties. He was sentenced to three years in prison on those charges. He also faces another pending felony charge of harassment in St. Louis County Circuit Court.