Federal agents and hazmat crews on Wednesday returned to the Irvine home of an 18-year-old for a second investigation into alleged science experiments, according to reports.

Agents from the FBI, Department of Justice, Environmental Protection Agency, and the Irvine Police Department were observed at the residence in the gated Altair community. The U.S. Attorney’s Office for the Central District of California confirmed a judicial search warrant was being executed, though the contents seized remain unclear.

This marks the second time in two days that federal authorities have visited the home. On Tuesday, FBI officials, hazardous material teams, and the bomb squad responded to reports from neighbors who noted a strange chemical odor and observed three industrial barrels.

The attorney for the family, CJ Ray, stated that the barrels were empty and had previously contained chemicals, but were not confiscated during the initial investigation in February. "The family is beyond frustrated that this is happening again, and that people are scared of what they don’t understand," Ray told NBCLA.

In February, federal authorities conducted a raid at the same home, then owned by a 17-year-old Amalvin Fritz. This earlier investigation was prompted by reports of suspicious items. During that search, chemical mixtures and formulas written on a whiteboard were discovered, leading the FBI to involve experts. No arrests were made during the February search.

The Irvine Police Department issued a statement Tuesday indicating that the Orange County Fire Authority and Irvine Police had responded to a report of a chemical odor. The FBI joined the investigation, and authorities assured the public that there were no evacuations and no known threat to the community. The multi-million dollar home is located in a neighborhood where properties average over $5 million.