Just four days after he was introduced as Arizona Diamondbacks manager, Wally Backman (search) was fired Friday following revelations he was arrested twice and struggled with financial problems.

Former Seattle manager Bob Melvin (search) will replace Backman. Melvin, fired by the Mariners the day after the season ended, was Bob Brenly's bench coach on Arizona's World Series championship team of 2001.

Arizona's management had been unaware of Backman's problems until they were reported in Tuesday's editions of The New York Times. Diamondbacks officials said they failed to do a criminal or financial background check on Backman.

"It's obviously a mistake on our part to have made a decision without having done the proper background work that could have been done, should have been done," managing partner Ken Kendrick said. "I take full responsibility for that, and I'm very sorry."

After details of his past problems surfaced in the Times and in the Phoenix-area media, the Diamondbacks hired a company to do an independent background check. The decision to replace Backman was made after seeing results of that investigation, Kendrick said.

"Had we, at the time we made the decision, had all the facts that we ended up having, we would not have named Wally our manager," Kendrick said.

Kendrick declined to say what other problems the club's probe may have uncovered.

"We're at a point where talking about this in that way is not really fair to Wally," Kendrick said. "We respect him and his family. He's a good family man. He has a loving wife and wonderful children. They don't deserve at this point, with this decision having been made, for there to be further scrutiny in their lives."

Backman was asked in his final interview whether there was anything in his past that the Diamondbacks should know, and he answered no, Kendrick said.

As a result of this week's failings, the Diamondbacks have instituted mandatory background checks on all key hires. One was conducted on Melvin, Kendrick said.

Backman managed in the minor leagues for eight seasons after a 12-year major league career, the first nine with the New York Mets. He was part of the 1986 Mets team that won the World Series title.

He had spent one year in the Diamondbacks organization, managing at Class A Lancaster, and was selected Sporting News minor league manager of the year for his performance.

The abrupt turnaround was an embarrassment for the organization in its first major decision since restructuring management and forcing out Jerry Colangelo, who had headed the franchise since its inception in 1998.

Backman, 45, had agreed Monday to a two-year contract.

"He's very disappointed but he understands and respects our decision," Kendrick said.

Backman never signed a contract and will be given no compensation, Kendrick said.

Backman was arrested in 2001 after a fight at his home involving his wife and one of her friends in Prineville, Ore. He pleaded guilty to misdemeanor harassment and was sentenced to 12 months' probation, ordered to undergo an anger management evaluation and donate $1,000 to the local Boys and Girls Club.

He was arrested, and later convicted, on a driving under the influence charge in Kennewick, Wash., in 2000.

A judge in Benton County, Wash., has ordered a hearing next month to determine if he violated his probation on the drunk driving charge. He served a day in jail and the rest of the one-year sentence was suspended on condition that he commit no new crimes.

The judge's order stems from the 2001 fight in Prineville. Backman has also had financial problems, filing for bankruptcy several years ago.

When Backman was hired, Kendrick raved about his intensity and "hard-nosed" attitude. Melvin is far more low-key.

Melvin managed the Mariners for two seasons was let go by Seattle and replaced by Mike Hargrove after the Mariners went 63-99. A close friend of Brenly, Melvin said he dearly wanted the Diamondbacks job and was willing to overlook the fact that he was not the team's first choice.

Wearing the World Series ring he earned with Arizona, Melvin said he wanted to restore the pride that the organization has felt in the past.

"This really is a dream come true. There's nowhere else I'd rather be than here," he said. "The goal here is to get us back to our glory days. There is a very rich history here, albeit a short one. We accomplished some incredible things here in a very short period of time and the goal is to get back to that."

Melvin, who lives in suburban north Phoenix, announced that former Diamondback Jay Bell would be the team's bench coach. Al Pedrique, who took over as interim manager when Brenly was fired last July, is a likely choice for his old job as third base coach, although no official announcement has been made.

Backman, Melvin and Montreal third base coach Manny Acta were the three finalists for the job.