Under pressure from a congressman, the Colorado school that stopped a valedictorian from delivering a commencement speech in which he planned to come out as gay has asked outside lawyers to review what happened.

In a letter on behalf of the school to Democratic U.S. Rep. Jared Polis, Denver lawyer Barry Arrington said Twin Peaks Charter Academy is hiring a law firm to look into the case. Polis had called for an independent investigation after school officials initially announced their probe would be internal.

The events in Longmont contrast with a decision by another Colorado school to allow its valedictorian to come out in her graduation speech.