Police have caught up with a suspect found dangling upside-down by his underwear on a six-foot-high fence in Adelaide overnight.

Key points: A 23-year-old Seaton man was arrested in Findon this morning

A 23-year-old Seaton man was arrested in Findon this morning He was charged with being unlawfully on premises and breach of bail

He was charged with being unlawfully on premises and breach of bail Police are also investigating a separate incident at Elizabeth Grove overnight

The man was arrested by police at Findon, in Adelaide's west, after reports of someone smashing windows at a house under construction.

Police said they were called to Trimmer Parade just before 3:00am this morning after a witness had yelled out at the suspect, causing him to run away.

The suspect was spotted by police nearby, but he ran off when the patrol approached.

"They lost sight of him, but soon found him dangling upside down from a six-foot fence by his underwear, after he became caught while trying to jump the fence," Senior Constable Matt Brown told ABC Radio Adelaide.

"So one day you're going to get caught with your pants down … and today was that man's day."

The 23-year-old Seaton man was arrested and charged with being unlawfully on premises, breach of bail and carrying an offensive weapon after a knife was also found in his pocket.

He was bailed to appear in the Port Adelaide Magistrates Court and police said investigations into the property damage would continue.

Police have urged anyone who sees or hears any suspicious activity on building sites, vacant premises, businesses or schools to call the police assistance line on 131 444.

Break-in at Elizabeth Grove

Elsewhere, South Australian police are also investigating a break-in at Elizabeth Grove, in Adelaide's north, where a man was assaulted.

Police said at about 5:20am today police and ambulance crews were called to a house in Deptford Street after reports of a group of four men armed with weapons had forced their way into a unit.

Police said the men threatened the occupant before they fled the scene.

The victim was taken to hospital with minor injuries and police suspect the incident was not random.

Anyone who may have witnessed the incident has been urged to call Crime Stoppers on 1800 333 000.