A public housing tenant has been sentenced to four months' jail after being caught red-handed throwing three glass bottles from his balcony, the Housing Department says.

Together with penalty points allotted earlier for hygiene-related offences, the tenant was served with a Notice-to-Quit after accruing more than 16 penalty points under the marking scheme for tenancy enforcement, and is pending an appeal hearing.

This is the most serious case detected by a special team of police-turned-security guards the department set up 18 months ago on a trial basis. They have successfully tracked down 12 offenders throwing objects from heights.

The three-member team mounted a round-the-clock surveillance at strategic locations or black spots within the bounds of public housing estates to detect and gather evidence to nail down offenders for such reckless acts.

24-hour surveillance

Deputy Director of Housing for Estate Management Lau Kai-hung said banking on the experience and expertise of the former police officers in information gathering and prosecution procedures, the team will assist estate management staff in follow-up work and investigation.

"Digital falling-object-monitoring systems and falling-object-monitoring closed-circuit televisions are also in place at strategic locations or black spots to pose a stronger deterrent effect on offenders," he said.

Mr Lau warned reckless acts of throwing heavy objects from height causing casualties or deaths may carry criminal liability, and called on tenants to prevent objects from falling as such offences carry seven penalty points.

With effect from January this year, the number of warnings has been reduced to one verbal and one written warning, and a tenancy is liable to termination when 16 points have been recorded within two years.

3,400 households allotted penalty points

Since the marking scheme was introduced in August, 2003, four households have been allotted more than 16 points, 81 more than 10 points and 3,394 have accrued penalty points.

Of the four households accruing more than 16 points, one was given a discretionary amendment to the Notice-to-quit, which could become ineffective if the tenant does not commit further hygiene-related misdeeds on or before the removal deadline on August 13.

The Appeal Panel is also considering another household's appeal and a decision will be made in two weeks' time, while appeals of the two remaining households are pending hearings.