We present multiwavelength photometry , high angular resolution imaging , and radial velocities , of the unique and confounding disintegrating low-mass planet candidate KIC 12557548b . Our high angular resolution imaging , which includes spacebased HST /WFC3 observations in the optical ( \sim 0.53 \mu m and \sim 0.77 \mu m ) , and groundbased Keck/NIRC2 observations in K ’ -band ( \sim 2.12 \mu m ) , allow us to rule-out background and foreground candidates at angular separations greater than 0.2″Â that are bright enough to be responsible for the transits we associate with KIC 12557548 . Our radial velocity limit from Keck/HIRES allows us to rule-out bound , low-mass stellar companions ( \sim 0.2 M _ { \odot } ) to KIC 12557548 on orbits less than 10 years , as well as placing an upper-limit on the mass of the candidate planet of 1.2 Jupiter masses ; therefore , the combination of our radial velocities , high angular-resolution imaging , and photometry are able to rule-out most false positive interpretations of the transits . Our precise multiwavelength photometry includes two simultaneous detections of the transit of KIC 12557548b using CFHT/WIRCam at 2.15 \mu m and the Kepler space telescope at 0.6 \mu m , as well as simultaneous null-detections of the transit by Kepler and HST /WFC3 at 1.4 \mu m . Our simultaneous HST /WFC3 and Kepler null-detections , provide no evidence for radically different transit depths at these wavelengths . Our simultaneous CFHT/WIRCam detections in the near-infrared and with Kepler in the optical reveal very similar transit depths ( the average ratio of the transit depths at \sim 2.15 \mu m compared to \sim 0.6 \mu m is : 1.02Â \pm 0.20 ) . This suggests that if the transits we observe are due to scattering from single-size particles streaming from the planet in a comet-like tail , then the particles must be \sim 0.5Â microns in radius or larger , which would favour that KIC 12557548b is a sub-Mercury , rather than super-Mercury , mass planet .