Police in New York City are investigating a grisly double murder-suicide in which they say a man decapitated his wife, slit the throat of their five-year-old daughter and then took his own life by hanging Wednesday night, just hours after the woman tried to get an order of protection.

According to the NYPD, at around 9.18pm officers responded to a 911 call requesting a welfare check inside an apartment at 151 West 121st Street in the Harlem section of Manhattan.

Upon entering the unit, officers found Yonathan Tedla, 46, Jennifer Schlecht, 42, and their five-year-old daughter, Abaynesh Schlecht Tedla, dead inside.

It is unclear how long the family had been dead before their bodies were discovered.

Schlecht's heartbroken father, Kenneth Schlecht, 74, tells New York Daily News that his daughter's marriage was unraveling, and that his son-in-law had threatened to 'take them all out' if Jennifer tried to serve him with divorce papers.

Spectrum News NY1 said neighbors described the couple and their young daughter as 'the perfect family'.

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Police say Yonathan Tedla (right), 46, beheaded his wife, Jennifer Schlecht (left), 42, and slit the throat of their five-year-old daughter, Abaynesh (center), before hanging himself

The carnage took place as Schlecht and Tedla were going through divorce proceedings

Horror inside: The building on West 121st Street in Manhattan on Wednesday became the site of a double murder-suicide in which a father beheaded his wife, killed their daughter and then himself

A sobbing woman is seen outside the building in Harlem on Thursday morning

NYPD detectives arrive on the scene of last night's carnage in Harlem Thursday

Officers are seen removed evidence bags from Schlecht and Tedla's home

Tedla was discovered in a bedroom, his wife in the bathroom, and their child in another bedroom, according to a press release from the police. The mother and daughter both had neck trauma.

The New York Daily News reported, citing unnamed sources, that Schlecht was found decapitated, with her severed head resting in her lap.

Her daughter suffered a cut so deep to her neck that she was partially beheaded.

The five-year-old's father was found hanging from a rope tied to a bedroom door.

Police seized a knife, believed to be the murder weapon, from the scene.

Tedla and Schlecht were reportedly going through divorce proceedings and were due in court just hours before the gruesome slayings.

Schlecht's brother contacted the authorities that evening, asking to check on his sister after failing to reach her by phone.

Kenneth Schlecht, Jennifer's father, tells the Daily News that the last time he spoke to his daughter was last Sunday and she was in tears.

'She said her husband had indicated that if she served him with divorce papers he would ruin her or take them all out, which was apparently what he did,' he said.

Jennifer and Yonathan Tedla, an immigrant from Ethiopia, met in the early aughts at Columbia University, where she was attending graduate school and he was working as an IT technician.

According to Kenneth, Jennifer and Yonathan's previously happy marriage began coming apart at the seams when they welcomed their daughter five years ago.

Around the time Abaynesh turned two, Jennifer got an order of protection against her husband, but decided to stay with him because she did not want her daughter to grow up without a dad.

The woman, believed to be a family member or a friend, appeared inconsolable and sought comfort from a man outside the crime scene

There was heavy police presence in and around the building where the slaughter took place. Children's drawings are seen taped to a second-floor window.

During her final, emotional phone call with her family over the weekend, Kenneth said his daughter informed them she was planning to go to court on Tuesday to get another protection order against Yonathan, but the courts were closed that day for Election Day.

Neighbors described Tedla to ABC 7 NY as a friendly and kind man who adored his wife and daughter.

The couple's across-the-street neighbor Ruben Natal-San Miguel told DailyMail.com in an interview that he knew the family and saw the husband almost every other day.

'They were just a normal, every-day family,' he said, describing them as 'lovely.'

Natal-San Miguel said he saw the parents taking their daughter out treat-or treating on Halloween and had their stoop decorated with spiderwebs for the holiday.

'They were part of the community, they were involved with the block association,' he said.

The Daily News reported that in 2016, Schlecht got a temporary restraining order against her husband because he was threatening her.

Schlecht (pictured kneeling in a white blouse) had worked on humanitarian problems affecting women around the world for 15 years

Earlier this year, Schlecht (second row from the bottom) was appointed senior adviser for emergency preparedness and response with the humanitarian organization Family Planning 2020

Schlecht had a Bachelor's degree in anthropology and a Master's degree in population and family health

A tribute tweeted by Family Planning 2020 read: 'Jennifer devoted her entire career to advocating for women and girls. We will all remember her for her life – and the thousands of lives she enriched – rather than the horrible way she died'

According to her LinkedIn page, Schlecht served as a senior adviser for emergency preparedness and response with the humanitarian partnership Family Planning 2020.

Beth Schlachter, executive director of FP2020, sent a statement to DailyMail.com addressing the tragedy.

'Jennifer Schlecht devoted her entire career to ensuring that women and girls in crisis situations have access to the best medical care possible including family planning and other reproductive health care,' it read. 'Most recently, she has been a vital part of the FP2020 family at the United Nations Foundation. She was a leader in the field of family planning and humanitarian response, and chose to work from New York so she could have more time with her darling daughter.

'She delighted in telling us about her daughter’s first day of kindergarten and the clothes she picked out all by herself. In addition to being an adoring mother, her contribution to the lives of women and girls who are living in crisis situations has been extraordinary.

'That she should die under such brutal circumstances is beyond understanding. But we will all remember her for her life – and the thousands of lives she enriched – rather than the horrible way she died. We are utterly devastated.'

Schlecht, one of three children in her family, graduated in 1999 from Boston University with a Bachelor's degree in anthropology and went on to earn a Master's degree in population and family health from Columbia University Mailman School of Public Health in 2004.

According to her online profile, Schlecht worked for 15 years in international relief and development, focusing on improving family planning for women and girls in areas affected by crises.

Last month, Schlecht gave a presentation at the Woodrow Wilson Center on the subject of reproductive care for female refugees.

Schlecht and Tedla welcomed their daughter, Abaynesh, in November 2014. Her name derives from an Amharic word that is translated as 'you are the Nile.'