Former X Factor finalist Mitchell Callaway has been arrested and charged with murdering a baby in Binnaway (near Coonabarabran) following several years of intense investigation by local detectives.

The charges come five years after the nine-month-old girl died at Coonabarabran Hospital and one week after police returned to a small town searching for evidence.

Emergency services were called to a home in Binnaway after the baby was found at 10am on July 23, 2018, in critical condition

Despite the efforts of staff at the hospital, she died a short time later.

Detectives from the Orana Mid-Western Police District immediately declared a crime scene at the Binnaway home and brought in forensic specialist police.

They concluded the death was suspicious and formed Strike Force King, an investigation by detectives from the Orana Mid-Western Police District has been ongoing ever since.

Then a break in the case reportedly came late last month, and officers returned to the Binnaway on May 31 to conduct a thorough search using metal detectors and on their hands and knees through the backyard of a modest brick home.

Police then sent away items they collected for forensic tests, and police appealed to the public for information.

Within a week - detectives arrested Callaway at this Bowraville home at 9.45 am on Thursday. He was taken to the station and charged with murder.

The 37-year-old appeared in Macksville Local Court later that day, where he the court refused him bail.

He is due to face court again next week.

Mitchell Callaway during an X Factor performance in 2011. Image: Channel 7.

Following the arrest and charging of the former X Factor finalist, the mother of the nine-month-old girl took to social media to describe “years of pain, suffering and grief”.

“After almost five years to the day, an arrest has finally been made ... all the years of pain, suffering, and grief and following my mother’s intuition,” she wrote on social media.

The mother said there was a “long road ahead” with court proceedings but that “the beginning of justice” had commenced after losing her “beautiful little girl.”

“She has been the reason I have continued to fight, live, and have made it this far,” she said.

“Not a day goes by that I do not miss you and wish you were here.

“This doesn’t bring you back, but it does bring you some peace and the justice you deserve.”

Callaway competed in season 3 of The X Factor in 2011 before being eliminated in the final showdown to Home and Away star Johnny Ruffo.

Mentored by singer Natalie Bassingthwaighte, he ultimately placing seventh in the competition.