A former Montgomery County police officer who was charged with helping her boyfriend operate a cocaine trafficking ring pleaded guilty Wednesday in U.S. District Court in Greenbelt to using police databases for financial gain.

Delores Culmer, 37, of Silver Spring admitted that she conducted wanted-persons checks on her boyfriend, one of his friends and someone her sister had a dispute with. She also ran unlawful motor-vehicle checks.

In all, prosecutors said, Culmer conducted 20 unlawful computer checks from August 2008 through September 2009. Culmer’s plea agreement did not mention the drug ring, but authorities described it in court papers that have been filed in the case.

Culmer, who most recently worked as a patrol officer, submitted a letter of resignation to Montgomery police last Thursday, her attorney, William C. Brennan, said in court.

Culmer was hired by Montgomery police in 2003, officials said. She had worked as a community services officer, helped with presentations on women’s safety and participated in programs for at-risk teenagers, according to a biography on a county Web site that police said she wrote.

In court Wednesday, Culmer dabbed at tears with a tissue. She is scheduled to be sentenced June 13, when she will face a maximum sentence of five years in prison and a $250,000 fine.

According to a criminal complaint, Culmer’s boyfriend told a confidential law enforcement informant that Culmer warned him of “law enforcement moves against him.” He also bragged that he could find anyone at any time, according to the court papers.

Federal authorities have not identified Culmer’s boyfriend. Prosecutors said in court papers that he has two drug convictions in Pennsylvania and has spent time behind bars. According to the documents, an informant told authorities that the man has moved large amounts of drugs to and from Arizona, Ohio, Pennsylvania and Maryland.

The fiance gave Culmer a $100,000 engagement ring and other expensive gifts, according to court papers. The man also allegedly gave her $30,000 in drug money that she used toward the down payment on a house in Silver Spring.

Culmer and her fiance met in Pennsylvania, where she had worked as a police officer in Pittsburgh, according to the criminal complaint.

Officials said an investigation into Culmer’s conduct began last year after the police force’s internal affairs unit received a tip. That led to a criminal investigation, which culminated with Culmer’s arrest.