The Food and Drug Administration this week posted what critics call an “underwhelming” epilogue to the devastating outbreak of botulism in babies, which was linked to spore-contaminated formula made by ByHeart. Despite clear tracking of the contamination, the regulator still doesn’t know how the bacteria arrived in the formula—or how to prevent it from happening again.

“The FDA’s investigation into the root cause is ongoing with a focus on ingredients,” the agency reported.

In the void, three companies at the center of the investigation are left pointing fingers at each other, with none publicly taking responsibility for the contamination.

The outbreak was identified in early November and was declared over by the FDA and Centers for Disease Control and Prevention on February 26. In the end, 48 infants across 17 states were sickened and hospitalized. Some are still recovering months after the life-threatening infection.