JACKSONVILLE, Fla. -

Just over this past weekend, the Jacksonville Sheriff's Office says it dealt with more than 20 missing persons cases.

"We run between 4,000 and 4,500 cases a year," said Detective V.A. Richardson, of JSO's missing persons unit.

Not all are children, but the majority of cases are. About 75 percent are 13- to 17-year-olds, 5 percent are 11 and younger, and the other 20 percent of cases are adults.

"By the grace of God we have been very fortunate in this city, except for here recently," Richardson said.

Richardson has been with the missing persons unit for seven years.

"We have several juveniles in this city who are repeat runaways, some as many as 25-30 times, some as young as 12 years old that have been gone 13, 14, 15 times," Richardson said.

Richardson says there are many indications a child is a potential runaway: change in dress, not hanging out with the same friends and/or parents don't know their friends, bad grades, drugs and alcohol use.

Other indications are reclusive behavior, rebellion, and no longer being able to communicate without a fight.

"Get them involved in some other things, take away that idle time that they have," Richardson said. "Get them off the computer, get them outside cheerleading, basketball, football, church."

And get to know your child's friends and their parents.

"I can't tell you how many missing children's cases we work and I ask the parents who are the friends, and they say, 'We have no idea,'" Richardson said. "That gives us zero to work with."

Richardson said simply walking back and forth to school is dangerous.

"I watch kids walk home from school that are little. I'm amazed," he said. "They may be in a group, but there's no adult. If you're an adult and your child is walking home, go meet them."

There is no specific age for a child's independence because every child matures at a different rate.

"If you give them a certain responsibility and they can't do a chore at home, I don't know how you could expect them to go out and be responsible for going to the movies at 13 or 14," Richardson said.

If you have a child you think may run away, JSO's Parent Help Center could be a great resource for you.

"It could be just a teen having some trouble, not being -- being unruly. Stuff like that," Richardson said. "It could be a teen who's been in trouble."

For more information on the Parent Help Center, go to theparenthelpcenter.com.