LOS ANGELES (CNS) - City Controller Ron Galperin said today he's preparing to subpoena the head of the union for Department of Water and Power employees, in the wake of his failure to turn over details on the financial activity of trusts that received more than $40 million from the utility over the past decade.

Galperin last month launched an audit of the Joint Training Institute and the Joint Safety Institute, a pair of independent trusts governed by boards made up of DWP and union officials.

Today was the deadline for the head of the International Brotherhood of Electrical Workers, Brian D'Arcy, who sits on the boards of both trusts, to submit the documents and appear for a meeting with Galperin's office, according to the controller.

Instead, D'Arcy sent a letter to Galperin's office saying the trust does not have to comply with the controller's request, the controller told reporters.

D'Arcy was not immediately available to respond to the controller's announcement.

Galperin said the LAPD will serve subpoenas instructing D'Arcy to show up for an audit meeting and furnish the requested documents.

The power of subpoena has only been exercised a few times by the controller's office during the last decade, Galperin said.

Mayor Eric Garcetti and City Attorney Mike Feuer were also on hand to discuss the subpoena.

``The city has the absolute right to follow the money,'' Garcetti said. ``This is ratepayer money and the ratepayers deserve to know exactly how it's being spent.''

Feuer said his office will take ``every step necessary to ensure'' Galperin gets the documents.

Feuer said if they are rebuffed again, they can ``go to Superior Court and seek a writ of mandate that would direct compliance with the subpoena.'' If that doesn't work, they have the option to seek a contempt of court order, he said.

Only DWP General Manager Ron Nichols, who also sits on the trusts boards, showed up this morning for the meeting, with boxes of some of the requested financial information, Galperin said.

The information Nichols provided could give them a ``good start,'' but D'Arcy needs to provide the rest of the documents, the controller said.

The union boss's inability to answer the ``simple question'' of ``how has this money has been spent'' raises questions about what actually happened with the money, Galperin said.

``You can't help but wonder, but I'm not reaching any conclusions at this time,'' he said.