Mother charged in death of missing 2-year-old Virginia boy Noah Tomlin was last seen when he was put to bed at about 1 a.m. Monday.

Police in Virginia now believe a 2-year-old boy missing for almost a week is dead, and on Saturday they charged his mother with three counts of felony child neglect.

Noah Tomlin is still missing, but Hampton Police Chief Terry Sult said at a news conference late Friday evening that authorities "believe [Noah] to be deceased," and that his mother, Julia Tomlin, is responsible.

"Tonight we are announcing an arrest related to the disappearance of Noah Tomlin," Sult said at a late Friday news conference. "We are arresting Julia Tomlin, 34-year-old Hampton woman, mother of Noah, in connection with his disappearance."

The toddler was last seen when he was put to bed at about 1 a.m. Monday at his mobile home in Hampton, police said.

His mother told police that went to check on him at around 11 a.m. Monday and didn't find him, authorities have said, adding that she reported him missing at 11:35 a.m. -- sparking a massive search.

"This leaves us a little bit speechless," Sult said Friday night. "But the search for Noah continues, we’ll never give up hope."

Sult said the search was "intensifying" with a "more specific focus, starting now." He did not offer further specifics.

More than 100 people attended a candlelight vigil for Noah on Saturday night, according to ABC Virginia station WVEC.

The FBI and several local law enforcement agencies have been involved in the five-day search.

"Since that time an intensive search has been underway," Sult told reporters Wednesday. "We're looking at everything from the child walking off to the abduction scenario."

"We have looked on land, water. We have checked trash, dumpsters. We have checked neighborhoods, houses, underneath buildings, in sheds," Sult said.

Tomlin served several months in prison in 2010 for felony child neglect, according to online state court records.

Norfolk, Virginia, CBS affiliate WTKR cited further court records in reporting this week that Tomlin spent five months behind bars, after her then 1-year-old daughter was severely burned when she sat the child down on a hot stove, and then failed to take her to the hospital for days. According to the records cited by WTKR, Tomlin had five kids at the time. Authorities have not disclosed how many children were in Tomlin’s care when Noah went missing on Monday.

The mother had been working with detectives in the search for little Noah, Sult said earlier in the week, and described her at the time as "holding up as about as well as you could expect under the circumstances."

Noah's mother told Hampton ABC affiliate WVEC via text on Wednesday, "I'm working real hard with law enforcement to help find my baby. I can't have my location known or whereabouts of my other children for their safety."

ABC News' Chris Francescani and Matt Foster contributed to this report.