CA * MURDER Continued from Page 1 A new look was installed by the Bradley Co. this morning, in Mt. the Auburn vestibule st.a part of the apartment block -but, minutes after the installation the lock would not secure the door. Jessie Gill, a tenant at No. 122, said she had called a meeting of all residents at her apartment this evening to discuss security. In another development, three close friends of the slain student voluntarily took lie detector tests at State Police Headquarters in Boston yesterday. Submitting to the tests were James Humphries, 27, classmate and boy friend of the Britton girl, and Mr. and Mrs. Don Mitchell, who lived across the hall. from Miss Britton. These three found the girl's body sprawled facedown on her bed at 12:40 p.m. last Tuesday. Cambridge police described the polygraph tests "not anything of major importance.' They said it was a routine thing designed to clear a few discrepancies in the recollections of the trio. James F. Reagan, Cambridge police chief, yesterday cracked down on the dissemination of information in the case to newsmen, ordering that "no statements will be made unless they are cleared through my office.' He said he made this move because of "the many inaccuracies that have been given out by investigators" or apparently developed through other sources.