By Eric Levenson, CNN

(CNN) -- Baltimore Police Commissioner Darryl De Sousa resigned Tuesday, less than a week after he was charged with failing to file income tax returns for three years.

"Today I received the resignation of Darryl De Sousa as Commissioner of the Baltimore Police Department and have accepted it," Baltimore Mayor Catherine E. Pugh said in a statement.

A national search for a new commissioner is now under way, and deputy commissioner Gary Tuggle will serve as interim commissioner, Pugh said.

De Sousa's legal trouble began last week when he was charged with misdemeanor counts of failing to file income tax returns in 2013, 2014 and 2015.

In a statement, he admitted to failing to file his federal and state taxes, but said he did file his 2016 taxes and received an extension for his 2017 taxes.

"While there is no excuse for my failure to fulfill my obligations as a citizen and public official, my only explanation is that I failed to sufficiently prioritize my personal affairs," he said.

"Naturally, this is a source of embarrassment for me and I deeply regret any embarrassment it has caused the Police Department and the City of Baltimore. I accept full responsibility for this mistake and am committed to resolving this situation as quickly as possible."

He was suspended with pay on Friday. Still, Mayor Pugh expressed her confidence in him last week and said this was a "personal matter."

Gene Ryan, the president of the Baltimore City Fraternal Order of Police Lodge #3, tweeted that officers were aware of the resignation.

"We are anxious to put these events behind us and hope that Mayor Pugh can quickly find a suitable replacement," Ryan said. "Our members deserve consistency in their leadership; however, as they are all highly trained professional law enforcement personnel, they will stay fully mission-focused in the interim."

Baltimore police issues

The resignation represents another setback for a police department marred by accusations of misconduct and one that is struggling to bring down a high homicide rate.

De Sousa had only spent a few months on the job. He was named commissioner in January after Mayor Pugh ousted former police commissioner Kevin Davis, saying that the city wasn't reducing violence fast enough.

"I'm impatient," Pugh said at a news conference in January. "We need more violence reduction. We need the numbers to go down faster than they are."

Baltimore had 343 homicides in 2017, according to the city's police department. Baltimore had a rate of 51.4 homicides per 100,000 residents in 2016, well above Chicago's 28.07 homicides per 100,000 residents and New York City's 3.9 per 100,000 residents.

Baltimore was the site of riots in April 2015 after 25-year-old Freddie Gray died in police custody. The Justice Department, under President Barack Obama, later issued a report saying that black residents were subject to disproportionate rates of stops, searches and arrests.

Last year, several police officers with the now-defunct Gun Trace Task Force were indicted on federal racketeering charges of robbing people, claiming fraudulent overtime and filing false affidavits. Two officers were convicted and six other officers pleaded guilty to federal charges.