LAKE PLEASANT, N.Y. (AP)—Robert Garrow, already convicted of one murder, may soon be facing prosecution for three other murders which he has ad mitted. Onondaga County Dist Atty. Jon K. Holcombe said Thursday night it was decided that grand jury indictments would be sought against Garrow for murders in Onondaga and Essex counties. However, Garrow first will be returned to Syracuse to face charges of sexually assaulting two young girls, Holcombe said. Garrow, 38, of Syracuse, was indicted in June 1973 on charges of assaulting the two girls in the Town of Geddes, Holcombe said. Garrow was convicted last month of murdering Philip Domblewski, 18, of Schenectady, and is serving a term of 25 years to life at Clinton Correctional facility at Dannemora. During his Hamilton County trial here, he testified that he killed three other persons in the summer of 1973: Alicia Hauck, 16, of Syracuse; Susan Petz, 21, of Skokie, Ill.; and Daniel Porter, 22, of Concord, Mass. Holcombe said he hasn’t decided whether to prosecute Garrow for the Hauck murder, but added, “he made a decision already that the Hauck case will go to the grand jury.”’ He did not indicate when that would be. At a meeting here Thursday, Holcombe and district attorneys William Intemann Jr. of Hamilton County and John McDonald of Essex County discussed further possible actions against Garrow.