WASHINGTON (AP) _ A man suspected in the serial killings of five women in Maryland pleaded guilty Tuesday to murdering a woman whose beaten body was found dumped in a northeast Washington alley.

Alton Alonzo Best, 31, pleaded guilty in District of Columbia Superior Court to second-degree murder and sodomy in the Jan. 15 killing of 20-year-old Janice Morton.

In exchange for the plea, prosecutors dropped charges of first-degree murder and rape against Best.

Best admitted in court that he beat the woman with his fists and strangled her with her brassiere after a night of using cocaine with Ms. Morton and two other people. Assistant U.S. Attorney Charles Hall said a witness saw Best dump the woman's nude body from a black van early on the morning of Jan. 15.

Similarities between Ms. Morton's death and the cases of five women whose bodies were found in a wooded area in Suitland, Md., last winter led authorities to believe the murders were linked.

''We've never eliminated him (as a suspect),'' Prince George's County police spokesman Bruce Gentile said after Best's plea. Gentile said police had found ''circumstantial connections'' between Best and some of the women found in Suitland but that Best has refused to talk to county detectives.

''There are a couple of others in his category (as suspects),'' said Gentile. ''Right now, we're backtracking, going back over what we've got. Our leads have dwindled.''

The victims, all light-skinned black women in their 20s, were found beaten and strangled between last Dec. 13 and Jan. 13. Police believe all were sexually assaulted.

Best's lawyer, Paul Leder, said he had ''never heard anything'' to support suggestions Best may have been involved in the other cases.

Best faces a maximum penalty of life in prison when he is sentenced July 22 in the Morton case.