It was likely agreed on (possibly via contract) to meet the compliance policy of the government agency. So I could see breach of contract. I don't know about

It was likely agreed on (possibly via contract) to meet the compliance policy of the government agency. So I could see breach of contract. I don't know about legal precedent for logs per se, but there is precedent for retention of other files. For instance HIPAA involves some well known regulations around keeping and destroying medical data.