Found this information that says quotes the Madison Illinois police chief as saying there was a possible suicide note in the car and that she did not return to the Illinois side of the bridge (nowhere else says this so I was looking for confirmation). I don't know if this source is legitimate and can't find this quote given anywhere else. Chris Burns is the chief of police in Madison Illinois.
“When we went back to the car and looked inside we found some personal belongings and what we believe to be a suicide note,” said Burns.
https://newsone.com/3703640/gift-kamau-missing-madison-illinois-college-student/
“When we went back to the car and looked inside we found some personal belongings and what we believe to be a suicide note,” said Burns.
https://newsone.com/3703640/gift-kamau-missing-madison-illinois-college-student/