A Houston drilling company is suing Frost Brown Todd, alleging that the Ohio-based Am Law 200 firm and a Texas funding manager failed to return $945,000 in escrow funds.

The plaintiffs, Drilling Structures International of Houston and its president and founder Philip Rivera, alleged in a petition filed Tuesday that they have been deprived of business opportunities valued at more than $10 million because that escrow money was not returned. The former Frost Brown lawyer mentioned in the complaint is no longer with that firm.

Frost Brown and the fund manager—Terra Master, of Nederland, Texas—face causes of action including breach of fiduciary duty, fraud by nondisclosure, fraud, negligent misrepresentation, conversion and statutory theft-conversion. The plaintiffs are seeking more than $1 million in damages, including punitive damages.