How to Press Charges for Assault and Battery

[citybythesea]

My question involves criminal law for the state of: Texas

My son was jumped, seriously injured and was in hospital for weeks. I went to police in town and filed reports on all individuals involved. The detective said that basically nothing could be done, even though they had previous records and were on probation. The local police here to do nothing with crimes like these. Most recently I was given documented proof where one of them admits to committing the serious injury to my son and threatens to do more injury to him.
Will this proof once and for good help me to press charges on them or not? Also if the local police do not do anything again, what is my next step and who do I contact next?

[Dogmatique]

Have you contacted the prosecuting attorney's office directly?

[citybythesea]

no I have not, should I do this with the new information too?