(a) A person commits an offense if, with specific intent to commit an offense, he does an act amounting to more than mere preparation that tends but fails to effect the commission of the offense intended.
(b) If a person attempts an offense that may be aggravated, his conduct constitutes an attempt to commit the aggravated offense if an element that aggravates the offense accompanies the attempt.
(c) It is no defense to prosecution for criminal attempt that the offense attempted was actually committed.
(d) Except as provided by Subsection (e), an offense under this section is one category lower than the offense attempted, and if the offense attempted is a state jail felony, the offense is a Class A misdemeanor.
(e) If the offense attempted is capital murder of a peace officer under Section 19.03(a)(1), the offense is a felony of the first degree, punishable by imprisonment in the Texas Department of Criminal Justice for life or for any term of not more than 99 years or less than 25 years.