He said the closing would affect 350 students: 200 in the kindergarten-through-sixth-grade program at 1209 Vine, and 150 seventh- through 11th-graders at 1225 Vine. The shuttering also impacts about 20 teachers and staff.
When Solomon began leasing that space for a learning center for older students last month, Weathington said, officials had no idea that a mental-health clinic that treats sex offenders was based there too.
He said the charter learned about the clinic when a patient asked a Solomon staffer for directions to it.
Although he did not know the clinic's name, a records search showed that ATA - Assessment and Treatment Alternatives - a nonprofit mental health clinic that serves juvenile and adult sexual offenders, has offices at 1225 Vine.
A staffer at the clinic who declined to give her name Friday said ATA had operated at that site for some time.
Since Solomon opened in the fall of 2012, it has offered a "blended" approach that combines online instruction to students in their homes with sessions in classrooms.
After learning of the clinic, Solomon stopped using the learning center at 1225 Vine and began offering only online instruction to its older students at home.
"We closed 1225 Vine about a week and a half ago because of what we learned," said Weathington.
As a cyber charter school, Solomon provides all students with iMacs to use at home.
"They were not missing any instructional time," Weathington said.
Solomon had been fighting the Education Department's attempts to revoke its charter on the ground that it was acting more like a traditional charter than a cyber charter and was even serving lunch. The department alleged that Solomon was not meeting the state requirement that cyber charters offer a significant portion of instruction to students online.
Although school districts authorize and oversee traditional charter schools, the Education Department is in charge of cyber schools because they offer online instruction to students across the state.
Wendy Beetlestone, Solomon's lawyer, said Friday that officials believed that the school could have weathered the state challenge to its blended-learning model. But she said that when health and safety issues emerged, the school decided to surrender the license because state law allows charter schools to be closed immediately for those reasons.
Education Department spokesman Timothy Eller said that as a result of Solomon's decision, the department would cancel a hearing on the school's operations that had been scheduled for November.
Weathington said Solomon also had been facing serious financial problems.
The state said Solomon was only authorized to enroll students from sixth through 11th grades. As a result, the School District of Philadelphia had refused to pay tuition for the 200 younger students who had enrolled this fall.
"How were we supposed to function?" Weathington asked. "We can't."
District spokesman Fernando Gallard said the district had received invoices from Solomon for 343 students. He confirmed that the district had withheld payment for the students in kindergarten through fifth grades because of the state's ruling.
Even so, Gallard said, the district had paid Solomon $675,000 so far this fall for the older students.
Weathington said Solomon would continue to provide instruction until Oct. 30 and was helping students and their families find new schools.
Parents were notified they could pick up their children's academic records at Solomon's offices at 1209 Vine beginning Monday. They also will be required to return their computers.