Updated

A month after pleading guilty to cocaine-possession charges, Republican Rep. Trey Radel of Florida refused to resign Thursday, saying he wants to "rebuild the trust" of voters.

At a news conference held the same day he left a drug and alcohol rehabilitation center, the 37-year-old freshman told reporters at his Cape Coral office that he will cooperate with congressional investigators who are looking into his conduct.

"I love what I do and I'm going to return to what I do, what you sent me to do in Washington D.C., which is working for you and your family while I relish mine," Radel told voters watching on live television in his district. "No one — no one will take away my passion when it comes to serving southwest Florida."

On Nov. 20, Radel pleaded guilty to a misdemeanor charge of cocaine possession and was sentenced to a year of probation. He admitted to purchasing 3.5 grams of cocaine from an undercover officer in Washington on Oct. 29. He entered rehab on Nov. 21.

The House Ethics Committee announced Monday that it was launching a formal investigation of the congressman.

Several GOP leaders, including Gov. Rick Scott, had asked him to resign. On Thursday, some of those same officials reiterated their calls for Radel to step down. In a statement, Scott said, "I'm glad that Trey has sought help, and it's my hope he continues to put his attention on rehabilitation and his family."

But standing with his wife at the evening news conference, Radel pledged to redouble his congressional efforts "with a clearer focus and a stronger mind" and regain the trust of his constituents. While he declined to say whether he would run for re-election, he gave what amounted to a campaign speech, vigorously defending his legislative record and repeatedly addressing TV viewers.

Radel, a former local news anchor, timed his announcement for the 6 p.m. newscasts.

"My situation isn't the end, and it's not the whole story," he said, ticking off a list of priorities, including reducing the deficit and protecting Social Security and Medicare.

Former Rep. Connie Mack IV, who represented the area for eight years before a failed run for Senate last year, has been mentioned as a possible primary challenger.

Radel said his drug and alcohol abuse never interfered with his official duties. "This was my personal issue on personal time," he said.

While court documents said the lawmaker purchased cocaine on several occasions prior to his bust in October, he maintained Thursday that he had only used the drug "a handful of times" beginning in college. His treatment, he said, was focused on alcoholism.

Asked about his support for drug testing food-stamp recipients, Radel said members of Congress "can and should be tested as well."

"Maybe it will help someone else in the future."

Radel had been in office for 10 months when he was charged. His district includes the Gulf Coast cities of Fort Myers and Naples.

The drug arrest derailed a seemingly promising career.

After a stint as a TV news anchor, he started a media-relations firm and hosted an early-morning conservative talk-radio show in southwest Florida. He married another news anchor and they had a baby.

On Thursday, his wife, Amy, called him a "great man" and said she supported his return to public life.

When he decided to run for Congress, he became involved in a bruising, six-way GOP primary, openly targeting opponents on the Internet and facing criticism for his firm's ownership of explicitly named websites. But he was backed by the local tea party movement and Republican luminaries, including Mack and Sen. Marco Rubio, and clinched the GOP nomination. He cruised to victory in November.

Things were seemingly going well for Radel. His wife was featured in a glowing local news segment about how the couple were adjusting to life in D.C., he had sponsored a handful of bills, and he was interviewed by several inside-the-Beltway publications. He was active on Twitter and wrote pieces for Buzzfeed about rap music. (He dubbed Public Enemy's "Fight the Power" a conservative anthem "because I believe when government expands it becomes a political tool meant to oppress.")

He championed cuts in sheep-farm subsidies, keeping good on his conservative promise.

Then, on Oct. 29, Radel attempted to buy $250 worth of cocaine from an undercover police officer in a Washington, D.C., neighborhood.

According to court documents, federal agents confronted the congressman and he invited them to his apartment, where he turned over a vial of the drug. A DEA official who spoke on condition of anonymity because he was not authorized to release details of the case in his own name said Radel was identified to authorities as a cocaine buyer by his suspected dealer.

For the next three weeks, Radel didn't skip a beat. He held a re-election fundraiser at a Naples country club, continued to cast votes and bashed "Obamacare" on Twitter. He did not tell House leaders about the bust until Nov. 19, when reporters broke the news about the case.

When his arrest became public, Radel said during a news conference that he had struggled with drug and alcohol abuse "off and on for years."

On Thursday, he said he would continue to build a support system "for the rest of my life," including attending daily meetings and "reconnecting with my spiritual side."

His first task, he said: setting up the family Christmas tree.