Detectives investigating the murder of Swiss student Manuela Riedo (17) believe there may be witnesses who have yet to come forward.
Gardaí in Galway today renewed their appeal for the public's help in trying to identify the last movements of Ms Riedo.
Swiss student Manuela Riedo
She was found strangled on waste ground near a walkway between Renmore and Ceannt train station on Monday October 8th.
Detectives believe people using the walkway that evening have yet to come forward.
"These people are urged to make contact with Galway so as that they can be eliminated from the investigation. The critical time is between 7.15pm and 8pm," a Garda spokesman said.
Ms Riedo was a member of a party of students who had travelled to the city for a two-week intensive course in English.
She was last seen when she left the home of her host family in Renmore at around 7pm to meet with friends in the city centre for a drink.
Ms Riedo was 5ft, 4in tall and around nine stone, with brown shoulder-length hair.
She was wearing a long grey and black coat with a red cardigan over a grey top beneath. Her jeans were grey and her boots were black suede. She was carrying a large black handbag with a cherry pattern.
Her body was discovered at 9.25 the following morning on the southern shore of Lough Atalia, below the Dublin-Galway railway line just half a mile from Ceannt Station. The walkway is a popular short cut used by pedestrians and cyclists.
Detectives have not ruled out a connection between Ms Riedo's murder and a number of sex attacks in the area and in Athlone, Co Westmeath, in recent months.
However, Supt Tom Curley, who is leading the investigation, said there is no evidence of a link.
The Garda spokesman said investigators were also interested to hear from anyone who has observed a change in the behaviour of people they know.
"Such changes may include an increase in the consumption of alcohol or drugs, missed work appointments or unscheduled leave or sick leave, leaving the area for unexplained reasons, appearing unusually nervous or anxious to friends or co-workers and, finally, attempting to change their appearance by cutting their hair or shaving off facial hair."
Anyone with information can contact the incident room at Mill Street on 091 538070 or the Garda confidential line on 1800 666 111.