BOSTON (AP) – Embattled Massachusetts House Speaker Salvatore DiMasi said Sunday he was resigning one of the most powerful positions in state government amid allegations a close friend used their relationship to push ticket-scalping legislation and paid off his in-laws’ legal bills.

DiMasi sent a letter to colleagues Sunday, saying his resignation as a state representative and as speaker would be effective at 5 p.m. Tuesday.

“No matter what the critics and cynics will say all my actions as state Representative and as Speaker were based solely on what I thought was in the best interests of my district and the people of the Commonwealth,” DiMasi said in his three-page letter.

“While my heart is heavy, it is also full. We have accomplished so much, together. No one can take away our legacy of triumphs on behalf of the citizens of the Commonwealth,” he said in the letter.

Growing evidence

DiMasi managed to win re-election as House Speaker earlier this month, despite a gathering cloud of questions into his involvement with close friend Richard Vitale, who has been charged with concealing his work as a lobbyist and having contact with the speaker while pushing a bill on behalf of ticket brokers.

And earlier this week, court documents revealed Vitale paid $7,500 in legal debts accumulated by DiMasi’s in-laws in September 2007.

“I never lost sight of the importance of all that we do and I urge you in the difficult fiscal times ahead to maintain this as The People’s House,” DiMasi told his colleagues.

DiMasi’s resignation breaks open a public succession battle that has been brewing in the background for months between Rep. John Rogers, the House majority leader, and Robert DeLeo, a Winthrop Democrat who serves as chairman of the powerful House Ways and Means Committee.

Four years of leadership

In a statement Sunday night, DeLeo thanked DiMasi for his service, particularly on the universal health care law and support for the life science initiative.

“I will work to restore faith in the House through meaningful ethics reform, to guide the state budget through perilous fiscal times, to fix our statewide system of transportation and to serve the commonwealth and its people with the knowledge that our actions and decisions will have lasting effects for all people of Massachusetts,” he said.

Rogers issued a statement last Friday that indirectly damned DiMasi’s four years of leadership.

“I pledge a new era of leadership dedicated to efficiency, transparency, accountability and overall effectiveness,” Rogers said in anticipation of DiMasi’s resignation.

“It’s time we finally put to rest all of the outside distractions that have been counterproductive so that we can refocus our efforts on the many important issues facing the commonwealth,” Rogers said.

Rogers himself paid $30,000 last year to settle a state investigation that found nearly $100,000 of his campaign funds went to a friend who made the mortgage payments on a Cape Cod vacation home owned by the representative and his wife.

Moving on

DiMasi said he would call for a caucus Wednesday to choose his successor.

DiMasi had been speaker since 2004, when Thomas Finneran resigned under his own ethics cloud. He was first elected to his seat representing Boston’s North End in 1978.

He said his decision to resign came Sunday, after consultation with his family.

“I am excited on the one hand to move on to other challenges and new opportunities. I am sad to leave the House of Representatives, which has been like home to me and the people who are like family,” he said.

“This decision was not made lightly and was made for a very simple reason: For me and my family it is time – time to move on, time to return to private life and time to return to my first professional love, the law,” DiMasi said.

DiMasi had earlier repaid an unusual $250,000 third mortgage he received from Vitale on his North End condominium after the loan was disclosed by The Boston Globe. That loan could have been illegal if Vitale were a lobbyist, since the state’s conflict-of-interest law prohibits members from accepting anything of value from lobbyists.

No direct allegations have been made against DiMasi, who has said he never spoke to Vitale about the bill.

Vitale has denied acting as a lobbyist. His attorney said the work he did for the Massachusetts Association of Ticket Brokers was exempt from the state’s lobbying registration requirements.

Attorney General Martha Coakley said Vitale was paid $60,000 in lobbying fees by ticket brokers interested in changing the state’s scalping laws. She said Vitale communicated directly with DiMasi before the bill passed the House last year. The legislation, which would have lifted restrictions on price markups by ticket brokers, died in the Senate.