A man who volunteered with disabled children over a 15-year stretch now stands accused of dozens of sexual offences, at least some of which allegedly involve kids he came across in the course of his work, Ottawa police said Wednesday.

Const. Chuck Benoit revealed few details about where Danyiel Walker volunteered or the nature of his involvement with children, but said the 41-year-old is believed to have offered volunteer support services at more than one facility.

Walker -- who faced several accusations earlier this year and was charged with new offences Wednesday -- now faces 49 sexual assault charges and 10 child pornography charges, police said. The case involves six alleged victims.

"Investigators believe that there's more victims out there," Benoit said in a telephone interview, adding the police are investigating more than one avenue through which Walker may have had access to disabled children.

Benoit said the investigation into Walker first began in January, when police received a tip about child porn images being uploaded from a local address. At the end of the month, police laid 10 child pornography-related charges against the man and issued a release announcing them.

Days later, an alleged sexual abuse victim came forward and triggered a broader investigation.

"That's actually what started the ball rolling," Benoit said. "From there we started to investigate the sexual assaults."

In late February, police laid 37 charges against Walker, which involved allegations from four people concerning incidents taking place between 2004 and 2019.

Police said at the time that the alleged male victims ranged in age from six to 24 and that at least one of them had a disability. Charges laid at that point included aggravated sexual assault, sexual exploitation, secretly recording someone nude, and sexual interference with children under the ages of both 16 and 14.

Benoit said Wednesday that two more alleged victims had since come forward, including at least one other disabled child, resulting in 12 new charges against Walker.

The latest allegations involve incidents between 2012 and 2019, Benoit said, adding the two alleged male victims range in age from three to 17.

Benoit did not disclose any of the facilities where Walker allegedly had connections.

One pediatric hospice operating on the grounds of the Children's Hospital of Eastern Ontario had issued a statement expressing "outright shock" at the time of the first round of charges against Walker.

Megan Wright, executive Director of Roger Neilson House, said Walker never volunteered at their facility, but was part of the community in ways she declined to discuss.

"Access to Roger Neilson House is given to families who find themselves needing our programs and services (including bereavement support) or at the discretion of other families in our care," the statement read. "To think that a member of our own tight-knit community could betray the trust of another family or families is nothing short of unimaginable. It's devastating."

Walker was scheduled to appear in an Ottawa court on Wednesday to face the latest charges.