Cambridgeshire Police should have been "more determined and thorough" in its search for a vulnerable mental health patient, a watchdog has ruled.
Steve Valentine, 30, went missing from a rehabilitation ward at a secure hospital in Cambridgeshire without his medication in October 2008.
Police carried out a search but his body was found in London the next day.
The Independent Police Complaints Commission (IPCC) said it was pleased the force has improved procedures.
The IPCC had investigated following a complaint from Mr Valentine's mother about the search.
Lack of communication
It found that Mr Valentine had made his way to London straight after leaving hospital but searches had continued in Cambridgeshire.
A duty inspector who should have progressed the search more diligently will receive management words of advice, the IPCC said.
The IPCC has also made a number of learning recommendations which it said the force has accepted, in particular to review its procedures around handling reports of absconders.
The investigation also found that a lack of force policy on absconders meant that control room supervisors did not automatically become involved.
Officers were consequently unaware of an agreed plan with the hospital and there was a lack of communication between the two, the IPCC said.
The Police National Computer should have been updated earlier so that other forces, including British Transport Police, were made aware, it added.
IPCC commissioner Rachel Cerfontyne said: "Our investigation has found that Cambridgeshire Police should have been more thorough and determined in their efforts to locate Mr Valentine.
"He was a vulnerable patient without his medication and some steps to progress the investigation and ensure other police forces were made aware were not taken.
"Mr Valentine apparently made his way to London straight after leaving the hospital so a search by police in Cambridgeshire would not have been fruitful, but officers did not have this knowledge at the time.
"I am pleased Cambridgeshire Constabulary has actioned our findings to improve procedures in circumstances where people abscond."