Birds of prey found dead in Ross-shire in the Highlands earlier this year were most likely not targeted deliberately, police have said.
More than 20 raptors were discovered at various locations in March and April.
Police Scotland confirmed that 16 of them - 12 red kites and four buzzards - were probably accidentally killed by pest control measures.
A reward is being offered for witnesses or further information which could help with the ongoing inquiry.
A criminal investigation into the deaths remains ongoing.
Det Supt Colin Carey said: "Investigations into the suspicious deaths of wildlife and especially raptors can be difficult and prolonged.
"The areas covered can be vast and it is seldom immediately apparent why a bird may have died.
"We work closely with partners to identify and thoroughly investigate all wildlife crime."
He added: "The death of the raptors in Ross-shire remains an on-going investigation during which we are endeavouring to establish all of the circumstances around this crime.
"We would ask anyone who may have further information to come forward."