Is it illegal for the developer to pry open the lock of the property office privately?

If it is for the purpose of vandalism, it is generally illegal. If it is for the purpose of theft, according to the value of stolen property, it reaches the criminal filing standard of theft and is convicted and punished for theft. Article 49 of the Law on Public Security Administration Punishment: Anyone who steals, swindles, robs, robs, extorts or intentionally damages public or private property shall be detained for more than five days and less than ten days, and may also be fined less than 500 yuan; If the circumstances are serious, he shall be detained for more than 10 and less than 15, and may also be fined less than 1000 yuan. Article 264 of the Criminal Law: Whoever steals public or private property in a relatively large amount, or commits repeated theft, burglary, armed theft or pickpocketing, shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention or public surveillance, and shall also or only be fined; If the amount is huge or there are other serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than ten years and shall also be fined; If the amount is especially huge or there are other especially serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than 10 years or life imprisonment, and shall also be fined or confiscated.