Question: Who destroyed the castle across the river from the castle built by the Auchinleck family in the 12th century?

Context paragraphs:
Dunderave Castle: Dunderave Castle is an L-plan castle built in the 16th century as the Scottish seat of the MacNaughton clan.  The castle lies on a small promontory on the northern shores of Loch Fyne, around 5 km north-east of Inveraray, Argyll.  The castle is in use as a residence.  The present castle was built after their previous castle was destroyed following a Plague infection.  The old castle, and remnants of McNaughton crannógs, can still be seen on the lochan known as the Dubh Loch at the head of Glen Shira.

Pollock Castle: Pollok Castle (Pollok Castle) was a tower house castle built by the de Pollocs in c. 12th or 13th century and became the seat of Clan Pollock, near Glasgow, Scotland.  The castle appears on Timothy Pont's map (1583–96), as a castle named "Pook" and also appears on Joan Blaeu's map of 1654.

Auchinleck Castle, East Ayrshire: Auchinleck Castle was a castle built on a rocky promontory on the eastern bank of the Lugar Water, East Ayrshire, Scotland across the river from Ochiltree Castle.  It was built by the Auchinleck family in the 12th century.

Château d'Ainay-le-Vieil: Château d'Ainay-le-Vieil is a 14th century castle built on the grounds of an earlier 12th century castle in Ainay-le-Vieil, Cher, France.  Château d'Ainay-le-Vieil is situated at an elevation of 168 meters.  After having bought the castle from Jacques Cœur, Charles de Bigny built a pre-Renaissance Louis XII style chateaux from 1500 to 1505.  The castle has been listed as a "Monument historique" since 1968 by the French Ministry of Culture.  The castle, now part of Jacques Cœur's tourist route, has been nicknamed "the little Carcassonne" (French: "le petit Carcassonne" ) because of its circular shape.  Today the castle is one of the best preserved fortresses of the 14th century.

Forres Castle: Forres Castle was a fort and castle built near Forres, Scotland.  The fort was destroyed in 850 by Vikings.  Forres was created a royal burgh by King David I of Scotland in 1140.  The castle, once a royal castle, was built as a motte and bailey castle and was strengthened in the 14th century.  It was demolished in 1297 by the adherents of Wallace.  King William the Lion and King Alexander II of Scotland visited and stayed at the castle.  King David II of Scotland stayed at the castle in 1346.  It was burned by Alexander Stewart, Earl of Buchan in 1390.  Held by the Dunbars of Westfield until the 17th century, it fell into ruins.  Nothing now remains above ground.

Sagiyama Castle: Sagiyama Castle (鷺山城 , Sagiyama-jō ) was a castle built in Mino Province in Japan during the late-Heian period (late 12th century); it was destroyed during the Sengoku period in the mid-16th century.  The castle's ruins are located in the present-day city of Gifu, Gifu Prefecture.  It stood at the peak of Mount Sagi, which was only 68 m .  Because the castle was built as a residence and not a defensive fortress, its location on a small mountain was of little consequence.

Auchinleck House: Auchinleck House is an 18th-century mansion in Scotland.  It is situated near the town of Auchinleck near Cumnock and Ayr in East Ayrshire.  The Auchinleck Estate has been inhabited since the 13th century, and the remains of Auchinleck Castle and Auchinleck Old House stand in the estate.  The house is protected as a category A listed building, while the two ruined dwellings are scheduled monuments.

Ochiltree Castle, East Ayrshire: Ochiltree Castle (meaning: "the lofty dwelling-place") was a castle built on a promontory by the Lugar Water, East Ayrshire, Scotland across from Auchinleck Castle.  Built by the de Colville family in the 12th century, it was destroyed in 1449, by Sir William Douglas.

Peebles Castle: Peebles Castle was a 12th-century castle built near Peebles, Scotland.  Peebles was created a royal burgh by King David I of Scotland in the 12th century.  The castle, once a royal castle, was built as a motte-and-bailey castle.  Nothing remains above ground.

Montrose Castle: Montrose Castle was a 12th-century castle built in Montrose, Angus, Scotland.  Montrose was created a royal burgh by King David I of Scotland in the 12th century.  The castle, once a royal castle, was built as a motte and bailey castle.  King Edward I of England accepted John Balliol's surrender of Scotland at the castle on the 10 July 1296.  The castle was destroyed by William Wallace in 1297.  The castle was noted to be in ruins in 1488.  Nothing now remains above ground.

Supporting paragraphs: Auchinleck Castle, East Ayrshire Ochiltree Castle, East Ayrshire
Answer: Sir William Douglas