"Our review is ongoing but so far there is absolutely no indication of any criminality or of any suicide pact," Assistant Chief Constable David Morris said.
All the suicides happened in or around Bridgend, nearly 20 miles west of Cardiff, within the past 13 months.
Police identified Jenna Parry, 16, as the latest victim. Her body was found hanging from a tree in the woods by a passer-by walking his dog in the village of Cefn Cribwr, five miles from Bridgend.
Morris complained about "sensational" media reporting adding to the problems facing the Bridgend area and called for more accurate coverage of the "cluster" of suicides. He singled out for his harshest criticism newspaper reports linking the deaths to some sort of Internet cult.
Police did say that a number of the victims used a social networking Web site that is popular with young Britons.
Morris was joined by the parents of Nathaniel Pritchard, a 15-year-old who took his life last week. They said their son may have been influenced by media reports they believe glamorized earlier suicides, and called for press restraint.
"We feel media coverage could trigger other young people, who are already vulnerable and feeling low, into attempting to take their own lives," Sharon Pritchard said.