The father of a six-year-old girl killed in the Sandy Hook massacre has been found dead from an apparent suicide.

Police said the body of Jeremy Richman was found in his Connecticut office building on Monday morning.

The 49-year-old's daughter Avielle Richman was among those killed in the 2012 Sandy Hook Elementary School shooting massacre.

Police said they were called to the Edmond Town Hall where Richman has an office at about 7am on Monday to investigate reports of a suicide.

Richman - who was a mental health advocate - was dead when first responders arrived, police said.

Jeremy Richman, 49, (right) was found dead from an apparent suicide at his Connecticut office on Monday. Richman and his wife Jennifer Hensel (left) lost their six-year-old daughter Avielle Richman (center) in the Sandy Hook massacre

'The death appears to be a suicide, but police will not disclose the method or any other details of the death, only to state the death does not to appear to be suspicious,' Newtown Police said in a statement.

Richman had two more children with his wife Jennifer Hensel after their daughter Avielle was killed.

Richman's body was taken to the Connecticut State Medical Examiner's office to undergo an autopsy.

'This is a heart breaking event for the Richman family and the Newtown Community as a whole, the police department's prayers are with the Richman family right now, and we ask that the family be given privacy in this most difficult time,' Police Lt. Aaron Bahamonde said.

Richman founded and ran the Avielle Foundation - a violence prevention charity - with his wife Jennifer Hensel in the wake of their daughter's death.

The Avielle Foundation was created within months of the tragedy with the goal of reducing violence and to conduct brain research to determine what leads to violence.

For Richman, the work became a full-time pursuit and he gave up his job as a researcher at the pharmaceutical company Boehringer Ingelheim to dedicate himself to the foundation.

Police said the body of Jeremy Richman was found in his Connecticut office building on Monday morning. His daughter Avielle Richman was among those killed in the 2012 Sandy Hook Elementary School shooting massacre

Police said they were called to the Edmond Town Hall where Richman has an office at about 7am on Monday to investigate reports of a suicide. The hall is pictured above during a memorial for the Sandy Hook victims

Their foundation provides grants for projects on topics including the effects that abuse, neglect and adversity have on the brain and the links between behavior and biochemistry.

Richman was the keynote speaker at the 2019 Violence Summit just last week at the FAU Brain Institute at Florida Atlantic University.

Richman and Hensel were honored for their advocacy by the psychiatry department at the Yale School of Medicine in 2016.

'The brain is just another organ and you don't have to be a neuroscientist to recognize that it can be healthy, it can be unhealthy, and that you need to feel comfortable advocating for your own brain health and the brain health of your loved ones,' Richman said back in 2016.

'We feel that the failure to do that led in large part to the tragedy at Sandy Hook.'

Richman and Hensel were among a group of Sandy Hook parents suing InfoWars host Alex Jones for calling the 2012 massacre a hoax on his show.

Richman founded and ran the Avielle Foundation - a violence prevention charity - with his wife Jennifer Hensel in honor of their daughter's death. They are pictured above just one month after the Sandy Hook massacre

The Avielle Foundation was created within months of the couple losing their daughter with the goal of reducing violence

Connecticut Senator Chris Murphy, who has lobbied for stricter gun laws since the shooting, tweeted on Monday that he devastated about Richman's death

The lawsuit filed in Connecticut say that Jones' comments on Infowars have tormented them and subjected them to harassment and death threats by his followers.

Connecticut Senator Chris Murphy, who has lobbied for stricter gun laws since the shooting, tweeted on Monday that he devastated about Richman's death.

'My god. This is awful, horrible, devastating news. Jeremy was a good friend and an unceasing advocate for better research into the brain’s violence triggers. He was with me in my office two weeks ago, excited as could be about the Avielle Foundation’s latest amazing work,' Murphy said.

Richman's death is the third suicide in a week that is related to school shooting massacres.

Sydney Aiello, who survived the Florida shooting at Marjory Stoneman Douglas High School last year, died by suicide last week.

The teenager, who graduated last year, had been diagnosed with PTSD.

A second student at the same school died on Saturday in what police said was an apparent suicide. That student has not been identified publicly.

Richman's daughter Avielle was among the 20 children shot dead when a gunman stormed Sandy Hook Elementary School on December 15, 2012

TWO PARKLAND MASSACRE SURVIVORS DIE BY SUICIDE: Two students at Florida's Marjory Stoneman Douglas High School have taken their own lives in just one week. Sydney Aiello, who survived the massacre last year, died by suicide last week. The teenager, who graduated from the school last year, had been diagnosed with PTSD. Sydney's family said she had suffered from 'survivor's guilt' after losing her best friend Meadow Pollack in the shooting that left 17 students and staff dead. Sydney Aiello, who graduated from Florida's Marjory Stoneman Douglas High School last year, took her own life last week after her family said she suffered from survivor's guilt A second student at the same school died on Saturday night in what police said was an apparent suicide. That student, who was a sophomore, has not been identified publicly. Parkland Mayor Christine Hunschofsky said Monday that community leaders, government officials, parents, police and others held an emergency meeting after the second student killed himself over the weekend. The February 14, 2018, shooting at the 3,200-student school killed 14 students and three staff members and wounded 17 others. Some students have begun counting the two suicides among the victims of the shooting. Advertisement

If you are in crisis, please call the National Suicide Prevention Lifeline at 1-800-273-TALK (8255) or contact the Crisis Text Line by texting TALK to 741-741.

For confidential support, call the Samaritans on 116123 or visit a local branch. See www.samaritans.org for details.

For confidential support in Australia LIFELINE: 13 11 14 www.lifeline.org.au or Suicide Call Back Service: 1300 659 467



