'They were very cold': Children find parents dead from apparent fentanyl overdose

A US mother and her commercial pilot husband were found "cold" in their bedroom by their four children having died from an apparent overdose from fentanyl.

Police say the children of 36-year-old Brian Halye and 34-year-old Courtney Halye found their bodies Thursday at their home in Centerville near Dayton, Ohio.

In one of the calls made to emergency services on Thursday morning (local time), Fox News reports the Halyes' oldest child was heard telling the dispatcher of the discovery.

"They were very cold," the boy said while his three sisters were heard crying in the background.

Courtney Halye and Brian Halye, a commerical pilot, were found dead from an apparent drug overdose. Source: Supplied

The children found their parents dead when they failed to take them to school, the son describing how his sisters found their dad "pale and there was black lines all over his face".

The Dayton Daily News reports that police records show that Courtney Halye's mother called police in January 2016 because she was worried that her daughter had threatened to harm herself.

Her mother, Nancy Casey, told police in January 2016 her daughter had been "hooked on drugs" on and off for about seven years.

Ms Casey told NBC News here daughter had Type 1 diabetes and suffered from depression but always seemed to be a "light in the room" and well liked.

The children found the couple in their bedroom. Source: Supplied

*UN drugs body places fentanyl ingredients on control list

Despite the initial report to police, she said she did not want her daughter to be characterised as an "addict" or "low-life".

"I don’t know if they decided they were going to party, or they got a hold of this bad stuff going around town," she said.

Brian Halye had previously told police that his wife had battled heroin and cocaine addiction for quite a while.

Mr Halye was a pilot for Spirit Airlines, which said he last flew March 10.

"Our hearts go out to the family, friends, and colleagues of Captain Halye," the airline said in a statement.

He had flown with the airline for nine years, but the company refused to comment on the last time he was drug tested when quizzed by CNN.

The airline noted that it runs random drug tests on all employees with positive results for drugs triggering an immediate dismissal.

Fentanyl is a powerful opioid said to be 100 times more powerful than morphine and the same drug that killed musician Prince last year.

The UN last week placed its ingredients on a controlled substances list.