Police are trying to trace the boyfriend of a 27-year-old doctor who died in hospital after swallowing sulphuric acid.

Detectives say they are anxious to speak to Andrew Gardner, 40, following the death of his partner Karenina Longe, a doctor from Birmingham.

Ms Longe died in the early hours of Sunday at Birmingham's Heartlands Hospital after drinking a quantity of sulphuric acid at her home in the city's Sheldon district.

Detective Chief Inspector Graham Bennett, of West Midlands police, said it was still unclear as to how Miss Longe came to swallow the acid.

He said: "The circumstances leading to her death leave me to believe that Andrew Gardner may provide vital information and help us in our inquiry."

He said the couple had a stormy relationship which had taken "a turn for the worse" in the past week.

Miss Longe had recently moved out of their rented home in Birmingham and had moved back into accommodation at the hospital.

She had returned to her home last Saturday.

Mr Bennett said: "Mr Gardner has not been seen since the incident and we urgently need to speak to him to ascertain what happened."

'Slow and painful death'

He said Mr Gardner, who was unemployed, would have previously worked in blood transfusion services.

He was originally from Zimbabwe but he had contacts in the London area.

The couple met 18 months ago and Mr Gardner moved to Birmingham in September 1999 after Miss Longe was employed as a senior house officer at Heartlands accident and emergency department.

Mr Bennett added: "From our inquiries so far we have determined that Karenina Longe was an intelligent lady who had no domestic or financial problems which would lead me to believe she would have taken her own her life."

Miss Longe was admitted to Heartlands hospital on Saturday afternoon.

The ambulance picked her up from her Sheldon home but despite undergoing surgery she died on Sunday afternoon.

Mr Bennett said they were investigating the possibility that the sulphuric acid was disguised in a drink.

He would not disclose how much acid was involved but added: "The Home Office pathologist has said a capful would be enough to kill a person. To swallow a toxic substance would be a very painful and slow death."

Mr Bennett said Miss Longe's partner was present at the house when the ambulance crew arrived but had since disappeared.

He added: "There is no evidence from the post-mortem that leaves me to believe she was force-fed the acid.

"We are treating this as a very suspicious death."