An adorable three-year-old boy fell to his death from an apartment window in Missouri while his father stepped outside to smoke a cigarette, a relative said. 

Travis Jr - who went by T3 - fell out of a high-rise window at Parkview Apartments in St. Louis around 2.30am on Friday, according to the St. Louis Metropolitan Police. 

He was staying with his father, who has not been named, while the little boy's mother was recovering in the hospital from a leg amputation, Terance Hardy, a relative of the boy, said in a GoFundMe fundraiser. 

The toddler was put to bed by his father just before he went outside for a smoke break, Hardy told KSDK. 

When T3's father returned, he couldn't find his son and started to panic. 

'He went down the hall searching, knocking on people's doors. He couldn't find him, and that's when they originally thought he was missing,' Hardy said. 

Officers then arrived at the building in response to a missing child report, where they discovered the boy's body outside the building. 

It remains unclear exactly which window he fell out of, but some neighbors claimed it was from the 11th floor, the outlet reported. 

It is also unknown if he fell from an apartment or hallway window, but according to Andrea Armour, T3's great-aunt, the windows in the hallway are always open. 

'These hallway windows, they stay open, they don’t lock, there’s no screen, none of that,' Armour told WOWT, adding that the tragedy happened at her apartment building. 

'It was my apartment, I wasn't at home. It was my apartment, where they were at. They were visiting me,' she explained. 

Although she was not home, Armour said T3's father had a spare key to her place, and he frequently checks in on her because of her health problems. 

She added that she has reported safety concerns about her apartment to building management in the past, though the specific complaints are unclear. 

The property is owned by St. Louis Housing Authority. 

The incident is being investigated by the St. Louis Metropolitan Police Department’s Child Abuse Unit. 

The St. Louis Housing Authority is also conducting a separate investigation, including reviewing surveillance footage from that morning and inspecting windows.

When contacted by the Daily Mail, a spokesperson with the St. Louis Metropolitan Police Department said no charges are set to be filed right now as the investigation is ongoing.

The Daily Mail contacted the St. Louis Housing Authority for comment. 

According to Hardy, T3's mother, Diamond Hamilton, is currently in rehab after gun violence caused her leg to be amputated. The circumstance of her shooting were unclear.

'For the past 2-3 years, she has been in and out of rehabilitation,' Hardy, Hamilton's cousin, wrote.  

'She is currently in rehab dealing with mental [and] emotional stress, and this has made her situation even worse!' 

During her recovery, T3's father's family had stepped in to help look after him, Hardy explained. 

He said she has two other children to take care of as well. 

As of Tuesday afternoon, more than $8,000 had been raised to help her during this difficult time. 

The grieving mother has taken to Facebook to share her painful loss, writing on Sunday: 'I prayed I prayed I prayed and asked god every night too [sic] protect my kids for me If I was away from y'all.' 

Family members gathered for a balloon release outside the apartment building on Sunday in memory of T3. 

A mass of people gathered outside holding blue balloons for him. 

'Just a vibrant little thing. I just want people to remember most how intelligent he was for a 3-year-old,' Hardy said. 'Just a ball of life.'