Cadaver dogs and crews combed through piles of garbage at a trash plant in Hartford, Connecticut, Wednesday, looking for evidence connected to a Jennifer Dulos' disappearance in May.
Investigators also executed a search warrant at the mansion of the missing mom's estranged husband, Fotis Dulos.
State Police were stationed in the neighborhood overnight, keeping watch until the search resumed Thursday morning.
Meanwhile, the children's 85-year-old grandmother Gloria Farber moved to seek custody Monday.
Farber, of New York City, filed her custody motion in Connecticut Superior Court the same day Fotis Dulos, the children's father, and his girlfriend, Michelle Troconis, were charged in the disappearance of 50-year-old Jennifer Dulos.
The children have been staying with the grandmother since Jennifer Dulos was reported missing on May 24, when she was last seen dropping the children off at school.
Fotis Dios, 51, and Troconis, 44, are charged with evidence tampering and hindering prosecution.
Arrest warrants link the pair to videos of trash bags being dumped in areas where Jennifer Dulos' blood was later found on clothing and other items.
The warrants show blood spatter and evidence of cleanup attempts were also found at her New Canaan home and police said they belied a "serious physical assault" occurred there.
The case has stunned residents of New Canaan, a wealthy suburb of New York City, which is about 60 miles (97 kilometers) away from the affluent Hartford suburb where Fotis Dulos and Troconis lived in a large home he used to live in with his wife and children.
Jennifer and Fotis Dulos have been embroiled in a contentious divorce and child custody case for the past two years. Their children range in age from 8 to 13 and include two sets of twins.
After Jennifer Dulos went missing, Fotis Dulos asked the divorce case judge to grant him custody of the children.
Court documents filed in the divorce case say Jennifer Dulos feared Fotis Dulos would harm her in some way in retaliation for her filing for divorce, and she noted he had a gun. Jennifer Dulos has primary custody of the children, with their father getting to see them every other weekend, before her disappearance .