New reports on the federal sex trafficking investigation into Rep. Matt Gaetz (R-Fla.) have revealed more details about the extent of the probe, including the seizure of his iPhone by federal agents over the winter and an associates cooperation against him since last year.

Gaetzs cellphone was seized when federal agents executed a search warrant, Politico reported Tuesday , citing interviews with three people who were told of the matter by the congressman, who changed his phone number late last year. His former girlfriends phone was also reportedly seized.

In another development indicating Gaetzs intensifying predicament, Gaetzs associate Joel Greenberg has reportedly been providing information since last year to investigators, according to The New York Times .

Greenberg has told investigators that he and Gaetz had sexual encounters with women in exchange for cash and gifts, two people briefed on the matter told the Times.

Greenberg, a former tax collector in Seminole County, Florida, began talking to investigators to secure leniency after realizing that the government had overwhelming evidence against him, according to the Times. He was indicted last June on a federal sex trafficking charge and dozens of other counts, including identity theft and bribery of a public official.

The investigation became public in recent weeks after Gaetzs involvement was reported. The congressman, a staunch conservative and Donald Trump ally, is accused of having sex with a 17-year-old and paying for her to travel across state lines, a violation of sex trafficking laws.

The Justice Department is also said to be investigating Greenberg's and Gaetzs involvement with multiple women who were recruited online for sex in exchange for cash payments.

It was previously reported that Greenberg was likely on the verge of cooperating with prosecutors after his attorney Fritz Scheller said last week that Greenberg would likely accept a plea deal. Im sure Matt Gaetz is not feeling very comfortable today, Scheller said at the time.

Gaetz has not been charged and denies any wrongdoing. He has said he never had sex with a minor or paid for sex.