She lived there with her mother Evelyn Sen, originally from Malaysia. Her father Graham Watson lives in Britain.
Neither could be reached for comment yesterday.
A post-mortem examination failed to provide clear answers about the cause of Maggie's death. But a second autopsy was completed days later and the results led police to believe the child's death was not accidental.
Des Gilmore lived two houses down from Maggie and her mother and was close to them.
He told the Herald he was happy someone would be held to account for Maggie's death.
"She was a beautiful little girl, a lovely little girl. She was adorable."
After Maggie's death her mother stayed away from the Moana Ave house the pair shared.
Mr Gilmore has seen her only briefly since then, driving past in a car.
Yesterday morning when he left for work, Maggie's mother's car was parked at the house but she was nowhere to be seen.
He had not spoken to Maggie's mother since the child's death but had been in contact with the woman's parents who live in Malaysia.
"I haven't heard from them since last year though. We have been kept very much in the dark," he said.
"I am definitely very happy someone has been charged. How could anyone do that to an innocent little 4-year-old? Somebody took her life and now that person, if they are found to be guilty, should pay the price."
Mr Gilmore said Maggie's death had affected him and his wife immensely.
"I think of Maggie all the time, every day," he explained.
"Every time I come home I pass the house and it's always on my mind. It is something that will never leave my mind. Maggie was a lovely, lovely little girl."
Police told the Herald on Sunday that they were in constant contact with Maggie's maternal grandparents who live in Malaysia and her aunt who lives in the United States.
The grandparents were dumbfounded when police informed them their inquiry had become a homicide investigation.
"When we found out that Maggie didn't pass away naturally, that it was somebody who did it to her ... each step is getting more and more traumatic for us, especially my wife," the grandfather said.
The child had spent about two-and-a-half months visiting them with her mother in Malaysia before she died.
