When Hawaii Attorney General Anne Lopez was asked about the early days of her investigation a month after historic fires ravaged Maui, she told reporters that she hoped state and county employees would “voluntarily participate” in the official review, but noted she’d resort to her subpoena power if she needed to.

Now she has. 

Lopez on Monday issued subpoenas to three Maui agencies who have faced public scrutiny for their response to the fires which killed at least 97 people: The Maui Emergency Management Agency, the County of Maui Department of Public Works, and the County of Maui Department of Water Supply.

Representatives for each have been summoned to appear on Dec. 11 to give testimony and present documents for examination.

Notably, the Maui Emergency Management Agency was once headed by Herman Andaya who resigned citing health reasons in the days following the fires during an uproar over his decision to not sound emergency sirens many believed would have helped save lives.

It is unclear if Andaya has cooperated with the investigation, but as part of the subpoena, Lopez requested records of all communications made by or to Andaya from 8 p.m. on Aug. 7, the evening before the fires, through Aug. 10.

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The head of the Maui Department of Water Supply, John Stufflebean, repeatedly declined to speak to NBC News in the wake of the fires, but told the New York Times the county’s water system “depressurized” as the fires spread. Copies of the subpoenas provided to NBC News indicate the attorney general has questions about the possible pressure loss.

In a news release, Lopez said other county agencies had been largely cooperative, but cited the need for “critical facts” from “key stakeholders” before the fact-finding phase of the investigation could wrap up. When it was first announced in August, the first phase was expected to last about three months and produce a comprehensive timeline of the incident.

“We appreciate the cooperation of the Maui fire and police departments, and while we continue to work through some issues, their leaders and line responders have been transparent and cooperative,” Lopez said.

A spokesperson confirmed to NBC News that while the investigation remains a comprehensive review of the fires and response, there is no current criminal investigation.

In late August, Lopez announced she’d tapped the non-profit Underwriters Laboratories Fire Safety Research Institute to assess the “policies and performance” of both Hawaii and Maui County agencies in preparing for and responding to the wildfires.