Scars — Kristine Kathryn Rusch

Rena lost everything when her husband and son died in a fiery car accident. Now she has only her daily swim at the rec center, where she hopes no one pays attention to her horrible burn scars.
But someone noticed -- the same someone who murders a lifeguard while Rena does her laps.
Only Rena can identify the killer, but the identification might prove more difficult than it seems...
“Kristine Kathryn Rusch's crime stories are exceptional, both in plot and in style.”
-- Mystery Scene Magazine