ATHENS, Greece—An internal probe has found no evidence backing claims that organized cells supporting the Nazi-inspired Golden Dawn party are active in Greece's police force.

But a police statement Wednesday said 10 of 15 officers arrested during the month-long investigation had, on an individual basis, "direct or indirect links" with allegedly illegal activities by the party.

The officers were arrested on suspicions including violating firearms and drug laws.

The probe also found a sharp rise in police misconduct since 2009.

Golden Dawn is under a criminal investigation sparked by last month's fatal stabbing of a Greek rapper, blamed on a party volunteer.

Its leader and two lawmakers have been jailed in pre-trial custody as alleged members of a criminal organization. Another six lawmakers have been stripped of immunity from potential prosecution.