Two children drowned and a third was hospitalized after falling into a pool at a residential daycare in northern California Monday.

Police responded to a home known as Happy Happy Daycare in San Jose for a wellness check at 9:05 a.m., FOX 2 KTVU reported.

Three children who had fallen into a backyard pool were all taken to the hospital, where two were pronounced dead and one is expected to recover. The ages of the children involved Monday were not provided.

Firefighters requested the response of police to investigate, but they have not said what led to the tragedy. 

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About five other children at the in-home daycare were accounted for, according to the local station.

The facility's website says it is licensed, and "following all safety protocols." 

The small family child care establishment is permitted to care for up to eight children at a time, The Mercury News reports. 

The newspaper says state licensing analysts cited the facility's licensees last month for failing to follow requirements documenting their checks every 15 minutes on sleeping children under their care. 

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Back in January, state officials noted the property's pool met all the requirements for such facilities, including a five-foot tall fence that could still be seen through, according to the outlet.

Fox News Digital reached out to the owner/operator, whose website says she has a Bachelor's degree in child development, but did not immediately hear back.

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The police department's homicide unit and the Santa Clara County district attorney will investigate the deaths, KTVU reported.