Texas Code of Criminal Procedure - CRIM P Art. 37.09. Lesser included offense

(1) it is established by proof of the same or less than all the facts required to establish the commission of the offense charged;

(2) it differs from the offense charged only in the respect that a less serious injury or risk of injury to the same person, property, or public interest suffices to establish its commission;

(3) it differs from the offense charged only in the respect that a less culpable mental state suffices to establish its commission;  or

(4) it consists of an attempt to commit the offense charged or an otherwise included offense.