Members of the Gilgo Beach homicide task force were seen walking out of the home with boxes, bags and filled-up bins.
They still haven't said why they returned to Heuermann's home as he awaits trial.
The task force's return comes 10 months after his arrest following a yearslong investigation.
Neighbors were caught off guard by the renewed police presence.
"Oh man, I can't believe it. Really it's shocking again," said Ettienne deVillers, who says he's lived next to Heuermann for 30 years.
He said state police also knocked on his door upon their return to the quiet Massapequa Park street.
"He kind of filled us in on and what's going on and that they got a search warrant and they're going to be here for a few days," deVillers said.
At least one of Heuermann's daughters was home when the task force returned. His wife, Asa Ellerup, and their son were apparently out of town.
"I spoke to Chris the other day, the son, and he told me that they were very upset that they delayed the trial," deVillers added.
Ray Tierney, the district attorney investigating the case, said "investigations evolve, new information comes in and as that new information comes in, it becomes necessary to take additional steps and that's what we're doing."
Tierney confirmed that the return sweep is part of the same investigation.
Four of the 10 known Gilgo Beach victims have been tied to Heurmann, who is facing murder charges.
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