A police investigation into a missing man who was found dead after a 15-day search has been criticised for failing to identify the case as high risk.

Daniel McSwiggan, 69, who had Alzheimer's disease, was last seen in Motherwell, North Lanarkshire on September 12.

His body was found at Strathclyde Park golf course on September 26.

Concerns about the handling of the search were raised by Mr McSwiggan's family and the case was referred to the Police Investigations and Review Commissioner (PIRC).

Investigators interviewed family members and medical professionals, as well as examining statements from officers and police command and control room records.

PIRC concluded the case should have been treated as high risk, rather than medium risk. "It should have been evident to Police Scotland that the man was a high risk, vulnerable missing person and Police Scotland should have graded the missing person assessment as high rather than medium risk," the report said.

"Although the investigation found Police Scotland's initial actions were appropriate, it also found it could have managed some aspects of the inquiry better."

PIRC also found that some officers did not keep notes of decisions made during the investigation, written statements were not taken from a number of key witnesses and CCTV footage, although viewed, was not seized and was lost.

One of the last sightings of Mr McSwiggan was on a bus but some officers working on the search were not aware they could access travel information from the bus company, PIRC said.

The commissioner, Professor John McNeill, has recommended a dedicated team for the management and conduct of vulnerable missing person investigations is set up.

Prof McNeill said: "There are lessons to be learned from this case. In particular, appointing a senior investigating officer, a dedicated person for family members to contact."