RIVERTON, Utah — A 36-year-old man has been arrested on multiple charges, including voyeurism and sexual exploitation of a minor, after a disturbing incident at a local gym involving an underage girl. Justan Grover, of Riverton, was taken into custody Sunday following an investigation launched after a 17-year-old girl reported that someone had been taking photos or videos of her while she was partially nude inside a tanning booth at VASA Fitness, located at 1777 W. 12600 South. The girl’s father alerted police after his daughter described the harrowing encounter, which occurred while she was preparing to use the tanning…