or intended victim who has attained the age of 12 years but has not attained the age of 18 years, or who the defendant believes has attained the age of 12 years but has not attained the age of 18 years, the maximum term of imprisonment authorized for that offense shall be increased by 5 years in addition to any penalty otherwise provided in this chapter. (b) Offenses involving minors under 12 If the conduct that violates this chapter involves a victim or intended victim who has not attained the age of 12 years, or who the defendant believes has not attained the age of 12 years, the maximum term of imprisonment authorized for that offense shall be twice that otherwise provided in this chapter. 2757. Offenses resulting in death or serious bodily injury (a) Offenses resulting in death A person who commits a violation of this chapter that results in the death of any person, shall be fined under this title or imprisoned for any number of years or for life, or both. (b) Offenses resulting in serious bodily injury A person who commits a violation of this chapter that results in serious bodily injury to any person, shall be fined under this title or imprisoned not more than 20 years, or both. 2758. Attempt (a) In General An attempt to violate section 2751(a), 2752(a), 2753(a), 2754(a), or 2755(a) shall be punishable in the same manner as a completed violation of that section. (b) Limitation For the purposes of sections 2751, 2752, 2753, 2754, and 2755, conduct consisting exclusively of a violation of 2751(b), 2752(b), 2753(c), 2754(b), and 2755(b) shall not constitute an attempted violation of 2751(a), 2752(a), 2753(a), 2754(a), and 2755(a). 2759. Repeat offenders (a) Maximum term of imprisonment The maximum term of imprisonment authorized for a violation of section 2751(a), 2752(a), or 2753(a)(1) after a prior sex offense conviction shall be twice the term of imprisonment otherwise provided by this chapter, unless section 3559(e) applies. (b) Definitions In this section— (1) the term prior sex offense conviction means