Sen. Patrick Brazeau says there were political reasons why he was suspended without pay in the midst of a spending scandal almost three years ago.

On Wednesday, the Crown dropped its charges of fraud and breach of trust against him, closing the long-running Senate expenses scandal. Brazeau was the last of four senators to be free of the allegations stemming from residence and travel expenses.

Brazeau's biggest legal battle is over, clearing the way for him to go back to work. On Thursday, he invited reporters to his office to take questions. But he had some of his own.

"Why did they make the decision to suspend me without pay and force me to repay wages that nobody else said that I had to pay back?" Brazeau said.

"It was politics. It wasn't administrative. It was politics."

Brazeau was suspended in 2013, along with Sen. Mike Duffy and Sen. Pamela Wallin. Mac Harb retired before he could face suspension. The suspensions lifted automatically when Parliament dissolved for the 2015 election.

When Brazeau's paycheque resumed, he says the Senate garnisheed the entire thing.

"Which employer across the country garnishes 100 percent of somebody's salary?" he said, adding that an independent audit had already found he didn't owe any money.

"What happened in the Senate... I believe was unjust and somebody needs to be held accountable," Brazeau said. "They haven't done enough and I'm going to start working on that right away."

The senator from Quebec still faces two charges related to allegations of driving under the influence. He acknowledged he's made bad choices recently, but said he's in therapy and ready for his return to the Senate.

"Yes, I made some bad decisions in the last three years, and I'm not trying to justify them, I'm taking responsibility for my bad decisions. But it was very hard," he said in French during a press conference where he easily handled questions in both official languages.

Brazeau said he didn't want to discuss his therapy, calling it personal in nature.

"There was substance issues and I admit it, but I'm working towards [recovering from] that as well, and I'm back in shape, trying to get in the best shape I can. And I'm healthy today," he said, adding he feels strong and ready to be back at work.

Now an independent senator, Brazeau said he regrets his partisanship when he was first appointed. But he hasn't once regretted accepting the position.

"I've always wanted to serve my country," he said.