A cheating father of six who killed his own wife and kids in a murder suicide before setting fire to their home lost his job weeks before the bloodbath.

Kristopher Karolkiewicz, 47, was let go from his role as Vice President of sales and marketing with the American Heart Association earlier this month, a statement said.

No further details on his dismissal were shared.

On Friday, Karolkiewicz shot and killed his wife Amanda, 39, and their children, aged five to 15, inside their Grand Haven Township, Michigan, home, investigators said.

Karolkiewicz then started several fires inside the $750,000 home before turning the gun on himself in what authorities have described as a murder-suicide.

In a statement to the Daily Mail, the American Heart Association said that Karolkiewicz worked for the organization from September of 2023 until earlier this month.

It added: 'We are devastated by the news out of Michigan, and our thoughts are with the loved ones of those who lost their lives in this tragedy.'

911 dispatch audio has also since been uncovered detailing how fire crews were called to white smoke billowing out of the property.

Karolkiewicz is pictured here with his wife Amanda, their kids, and Amanda's parents, Steve and Becky Lawwill

It emerged earlier this week that Karolkiewicz had cheated on his wife six years ago with an intern at his former job

'We're given a 10-7 for a residential fire at 14936 Riverside Trail. White smoke coming out of the window,' a fire dispatcher said.

'Full of smoke seen from the outside and smells electrical,' the dispatcher continued before a crew responded 40 seconds later confirming they were on their way.

It emerged earlier this week that Karolkiewicz had cheated on his wife six years ago with an intern at his former job, who Amanda described as 'younger' and 'wilder.'

She forced him to switch jobs in the aftermath of the affair but struggled with the pain of it.

Amanda detailed the affair in a series of Reddit posts unearthed by the Daily Mail in which she spoke about the unexpected birth of their youngest son two years ago.

Their youngest was born amid the couple's apparent battle to strengthen their marriage, which Amanda claimed was destroyed by Kristopher's infidelity.

The couple, who were wed in 2009, met while Amanda was interning at the company where Kristopher worked, her posts revealed.

The affair, which appears to have occurred more than six years ago, took place while Amanda was child-rearing.

The family of eight was found dead inside their $750,000 home in Grand Haven Township, Michigan, on Friday morning

Investigators say Kristopher shot and killed his wife and their children, aged 5 to 15, and started several fires throughout the house, before turning the gun on himself

'I was five babies in, and was actually not in bad physical shape, but I was in the trenches of little kids, and just couldn't be who I was before,' she said.

She felt so belittled by the affair that she spent Kristopher's work bonus on Botox, Invisalign, hair extensions and new clothes in a bid to make herself feel 'pretty.'

Kristopher was no stranger to cosmetic procedures himself, with Amanda revealing that he'd had an eye lift, known as an upper blepharoplasty, in one Reddit post.

Amanda said she 'lost tons of weight during the aftermath,' but despite her physical glow-up, she 'never felt better' and 'internally blamed' herself for not being 'enough.'

Amanda and her children's deaths have been ruled a homicide, and Kristopher's has been ruled a suicide, the Ottawa County Sheriff's Office said.

It remains unclear how exactly the blazes began, and Michigan State Police arson investigators are looking into the case.

Four of the six children were Kristopher's biological children. The other two were adopted by the couple.

None of the children has been named, but four of them were boys, aged 15, 12, 11 and five. Their daughters were 11 years old, police said.

The family's pets also died after inhaling smoke from the fires too.