The two men arrested today in connection with the 1999 murder of Ms Raonaid Murray, in Glenageary, Co Dublin have been released without charge.
The men were detained separately in Lucan and Wicklow this morning.
A Garda spokesman said it was not expected that a file would be sent to the DPP.
Ms Murray (17), from Silchester Park, Glenageary, was attacked and killed close to her Co Dublin home on September 4th, 1999.
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She was stabbed several times at about 12.10 a.m. and was found about 20 minutes later.
Gardaí have interviewed more than 9,000 people and taken more than 3,000 statements in the ongoing investigation.
A renewed appeal for help from the public was made last month to coincide with the day Ms Murray would have been 21.