Detectives face "unprecedented" pressure due to the Greenvale hotel crush and other recent deaths in Northern Ireland, a senior officer has said.
PSNI Detective Inspector Darren McCartney is investigating the tragedy where three teenagers died last month plus several other serious incidents.
He recently rang a coroner's office to complain about the rescheduling of a hearing and reminded coroner Paddy McGurgan of his heavy workload.
PSNI barrister Mark Robinson told a Belfast coroner's court: "Serious Crime Branch has been subjected to unprecedented demand over the recent number of weeks."
The Greenvale hotel inquiry in Cookstown, Co Tyrone, has involved sifting through hundreds of witness accounts.
Lauren Bullock, 17, Morgan Barnard, 17, and 16-year-old Connor Currie died.
Mr McGurgan wants to make a speedy decision on whether vulnerable Co Antrim man Mark Gourley is dead ahead of any inquest.
He is seeking a definitive response from police within a fortnight.
Mr Gourley, from the Castlemara estate in Carrickfergus, was reported missing in March 2009. He was last seen in the Burney's Lane area of Glengormley.
In 2013, police investigating his disappearance began a murder inquiry.
Only after a coroner pronounces on death can an inquest be scheduled.
It will be at least a year away due to competing demands on the coroner's diary.
Mr Gourley's father is unwell, Mr McGurgan observed.
Police officers' response to Tyrone hotel stampede tragedy to be investigated by Ombudsman
Only 23 lines of inquiry about his disappearance remain outstanding out of almost 600, the police barrister told the hearing.
Mr McGurgan said: "We all have a lot of work to do.
"It is insufficient as a reason to advance that he (DI McCartney) has been involved in quite a lot of other things.
"I am not content with the reason he has advanced with regards to the delay being the amount of work he has to deal with."
The coroner said when he moved hearings to accommodate lawyers it was often at great inconvenience to himself.
"It is totally inappropriate that he rings my office and says something along those lines to my staff."
Police have this week stepped up their murder investigation into the disappearance of Co Down woman Lisa Dorrian from a caravan park.
Two arrested in connection with the murder of Irishwoman Lisa Dorrian
They are also probing the killing of community worker Ian Ogle in east Belfast, as well as the death of Pat Ward in Clogher in Co Tyrone in February.
A barrister for the coroner, Philip Henry, said the working hypothesis was that Mr Gourley was more likely to have died on land and his body disposed of at sea.
He added: "It is unlikely that death occurred at sea."
A police opinion on whether he is dead is due by April 18 and the coroner said he expects to make his determination on May 1.
Mr McGurgan said: "I need something to be able to make a decision upon with regards to moving this matter forward.
Murdered Belfast man Ian Ogle died with 'unparalleled bravery', funeral told
"There will be no more slippage, there has been enough slippage already."
Detective Superintendent Jason Murphy, who leads the PSNI's Major Investigations Team, said: "We recognise our legal obligations and we will continue to work expeditiously with the coroner's office to meet the deadlines required.
"It has been a particularly busy period for Serious Crime Branch, particularly the major investigation teams in recent months."
